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Springer Handbook of EnzymesSupplement Volume S2

Dietmar Schomburg andIda Schomburg (Eds.)

Springer Handbookof Enzymes

Supplement Volume S2Class 2TransferasesEC 2.1–2.7.10

coedited by Antje Chang

Second Edition

1 3

Professor Dietmar Schomburg Technical University Braunschweige-mail: [email protected] Bioinformatics & Systems Biology

Langer Kamp 19bDr. Ida Schomburg 38106 Braunschweige-mail: [email protected] Germany

Dr. Antje Change-mail: [email protected]

Library of Congress Control Number: 200921144

ISBN 978-3-540-85696-2 2nd Edition Springer Berlin Heidelberg New York

The first edition was published as the “Enzyme Handbook, edited by D. andI. Schomburg”.

This work is subject to copyright. All rights are reserved, whether the whole or part of the material isconcerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation,broadcasting, reproduction on microfilm or in any other way, and storage in data banks. Duplicationof this publication or parts thereof is permitted only under the provisions of the German CopyrightLaw of September 9, 1965, in its current version, and permission for use must always be obtainedfrom Springer. Violations are liable to prosecution under the German Copyright Law.

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A complete list of all enzyme entries either as an alphabetical Name Index or asthe EC-Number Index is available at the above mentioned URL. You candownload and print them free of charge.

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Preface

Today, as the full information about the genome is becoming available for arapidly increasing number of organisms and transcriptome and proteomeanalyses are beginning to provide us with a much wider image of protein regu-lation and function, it is obvious that there are limitations to our ability to accessfunctional data for the gene products – the proteins and, in particular, for en-zymes. Those data are inherently very difficult to collect, interpret and stan-dardize as they are widely distributed among journals from different fields andare often subject to experimental conditions. Nevertheless a systematic collec-tion is essential for our interpretation of genome information and more so forapplications of this knowledge in the fields ofmedicine, agriculture, etc. Progresson enzyme immobilisation, enzyme production, enzyme inhibition, coenzymeregeneration and enzyme engineering has opened up fascinating new fields forthe potential application of enzymes in a wide range of different areas.The development of the enzymedata information systemBRENDAwas started in1987 at the German National Research Centre for Biotechnology in Braun-schweig (GBF), continued at the University of Cologne from 1996 to 2007, andthen returned to Braunschweig, to the Technical University, Institute of Bio-informatics & Systems Biology. The present book “Springer Handbook of En-zymes” represents the printed version of this data bank. The information systemhas been developed into a full metabolic database.The enzymes in this Handbook are arranged according to the Enzyme Com-mission list of enzymes. Some 5,000 “different” enzymes are covered. Fre-quently enzymes with very different properties are included under the sameEC-number. Although we intend to give a representative overview on the char-acteristics and variability of each enzyme, the Handbook is not a compendium.The reader will have to go to the primary literature for more detailed informa-tion. Naturally it is not possible to cover all the numerous literature referencesfor each enzyme (for some enzymes up to 40,000) if the data representation is tobe concise as is intended.It should bementioned here that the data have been extracted from the literatureand critically evaluated by qualified scientists. On the other hand, the originalauthors’ nomenclature for enzyme forms and subunits is retained. In order tokeep the tables concise, redundant information is avoided as far as possible (e.g.if Km values are measured in the presence of an obvious cosubstrate, only thename of the cosubstrate is given in parentheses as a commentary without refer-ence to its specific role).The authors are grateful to the following biologists and chemists for invaluablehelp in the compilation of data: Cornelia Munaretto and Dr. Antje Chang.

BraunschweigWinter 2008 Dietmar Schomburg, Ida Schomburg

VII

List of Abbreviations

A adenineAc acetylADP adenosine 5’-diphosphateAla alanineAll alloseAlt altroseAMP adenosine 5’-monophosphateAra arabinoseArg arginineAsn asparagineAsp aspartic acidATP adenosine 5’-triphosphateBicine N,N’-bis(2-hydroxyethyl)glycineC cytosinecal calorieCDP cytidine 5’-diphosphateCDTA trans-1,2-diaminocyclohexane-N,N,N,N-tetraacetic acidCMP cytidine 5’-monophosphateCoA coenzyme ACTP cytidine 5’-triphosphateCys cysteined deoxy-d- (and l-) prefixes indicating configurationDFP diisopropyl fluorophosphateDNA deoxyribonucleic acidDPN diphosphopyridinium nucleotide (now NAD+)DTNB 5,5’-dithiobis(2-nitrobenzoate)DTT dithiothreitol (i.e. Cleland’s reagent)EC number of enzyme in Enzyme Commission’s systemE. coli Escherichia coliEDTA ethylene diaminetetraacetateEGTA ethylene glycol bis(-aminoethyl ether) tetraacetateER endoplasmic reticulumEt ethylEXAFS extended X-ray absorption fine structureFAD flavin-adenine dinucleotideFMN flavin mononucleotide (riboflavin 5’-monophosphate)Fru fructoseFuc fucoseG guanineGal galactose

IX

GDP guanosine 5’-diphosphateGlc glucoseGlcN glucosamineGlcNAc N-acetylglucosamineGln glutamineGlu glutamic acidGly glycineGMP guanosine 5’-monophosphateGSH glutathioneGSSG oxidized glutathioneGTP guanosine 5’-triphosphateGul guloseh hourH4 tetrahydroHEPES 4-(2-hydroxyethyl)-1-piperazineethane sulfonic acidHis histidineHPLC high performance liquid chromatographyHyl hydroxylysineHyp hydroxyprolineIAA iodoacetamideIC 50 50% inhibitory concentrationIg immunoglobulinIle isoleucineIdo idoseIDP inosine 5’-diphosphateIMP inosine 5’-monophosphateITP inosine 5’-triphosphateKm Michaelis constantl- (and d-) prefixes indicating configurationLeu leucineLys lysineLyx lyxoseM mol/lmM millimol/lm- meta-Man mannoseMES 2-(N-morpholino)ethane sulfonateMet methioninemin minuteMOPS 3-(N-morpholino)propane sulfonateMur muramic acidMW molecular weightNAD+ nicotinamide-adenine dinucleotideNADH reduced NADNADP+ NAD phosphateNADPH reduced NADPNAD(P)H indicates either NADH or NADPH

X


NBS N-bromosuccinimideNDP nucleoside 5’-diphosphateNEM N-ethylmaleimideNeu neuraminic acidNMN nicotinamide mononucleotideNMP nucleoside 5’-monophosphateNTP nucleoside 5’-triphosphateo- ortho-Orn ornithinep- para-PBS phosphate-buffered salinePCMB p-chloromercuribenzoatePEP phosphoenolpyruvatepH -log10[H+]Ph phenylPhe phenylalaninePHMB p-hydroxymercuribenzoatePIXE proton-induced X-ray emissionPMSF phenylmethane-sulfonylfluoridep-NPP p-nitrophenyl phosphatePro prolineQ10 factor for the change in reaction rate for a 10�C temperature increaseRha rhamnoseRib riboseRNA ribonucleic acidmRNA messenger RNArRNA ribosomal RNAtRNA transfer RNASar N-methylglycine (sarcosine)SDS-PAGE sodium dodecyl sulfate polyacrylamide gel electrophoresisSer serineT thyminetH time for half-completion of reactionTal taloseTDP thymidine 5’-diphosphateTEA triethanolamineThr threonineTLCK Na-p-tosyl-l-lysine chloromethyl ketoneTm melting temperatureTMP thymidine 5’-monophosphateTos- tosyl- (p-toluenesulfonyl-)TPN triphosphopyridinium nucleotide (now NADP+)Tris tris(hydroxymethyl)-aminomethaneTrp tryptophanTTP thymidine 5’-triphosphateTyr tyrosineU uridine

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U/mg mmol/(mg*min)UDP uridine 5’-diphosphateUMP uridine 5’-monophosphateUTP uridine 5’-triphosphateVal valineXaa symbol for anamino acidof unknownconstitution inpeptide formulaXAS X-ray absorption spectroscopyXyl xylose

XII


Index of Recommended Enzyme Names

EC-No. Recommended Name Page

2.4.1.244 N-acetyl-b-glucosaminyl-glycoprotein 4-b-N-acetylgalactosaminyltransferase . . . . . . . . . . . . . . . . . 201

2.7.1.157 N-acetylgalactosamine kinase . . . . . . . . . . . . . . . . . . 2682.1.3.9 N-acetylornithine carbamoyltransferase . . . . . . . . . . . . . . 542.3.1.184 acyl-homoserine-lactone synthase . . . . . . . . . . . . . . . . 1402.6.1.85 aminodeoxychorismate synthase (formerly EC 6.3.5.8) . . . . . . . . 2602.4.1.233 anthocyanidin 3-O-glucosyltransferase

(deleted, the enzyme is identical to EC 2.4.1.115) . . . . . . . . . . 1522.4.1.238 anthocyanin 3’-O-b-glucosyltransferase . . . . . . . . . . . . . . 1762.3.1.172 anthocyanin 5-O-glucoside 6’’’-O-malonyltransferase . . . . . . . . 652.3.1.171 anthocyanin 6’’-O-malonyltransferase . . . . . . . . . . . . . . . 582.6.1.84 arginine-pyruvate transaminase . . . . . . . . . . . . . . . . . 2562.6.1.78 aspartate-prephenate aminotransferase . . . . . . . . . . . . . . 2352.3.1.177 biphenyl synthase . . . . . . . . . . . . . . . . . . . . . . . 832.1.1.160 caffeine synthase . . . . . . . . . . . . . . . . . . . . . . . . 402.5.1.67 chrysanthemyl diphosphate synthase . . . . . . . . . . . . . . . 2182.3.1.182 (R)-citramalate synthase . . . . . . . . . . . . . . . . . . . . 1312.4.1.235 cyanidin 3-O-rutinoside 5-O-glucosyltransferase . . . . . . . . . . 1612.3.1.175 deacetylcephalosporin-C acetyltransferase . . . . . . . . . . . . . 772.3.1.170 6’-deoxychalcone synthase. . . . . . . . . . . . . . . . . . . . 562.3.1.178 diaminobutyrate acetyltransferase . . . . . . . . . . . . . . . . 862.6.1.83 LL-diaminopimelate aminotransferase . . . . . . . . . . . . . . . 2532.4.1.241 digalactosyldiacylglycerol synthase . . . . . . . . . . . . . . . . 1852.7.7.65 diguanylate cyclase . . . . . . . . . . . . . . . . . . . . . . . 3312.1.1.161 dimethylglycine N-methyltransferase . . . . . . . . . . . . . . . 482.7.4.24 diphosphoinositol-pentakisphosphate kinase . . . . . . . . . . . . 3162.5.1.68 Z-farnesyl diphosphate synthase . . . . . . . . . . . . . . . . . 2232.4.1.236 flavanone 7-O-glucoside 2’’-O-b-L-rhamnosyltransferase. . . . . . . 1622.4.1.237 flavonol 7-O-b-glucosyltransferase . . . . . . . . . . . . . . . . 1662.4.1.239 flavonol-3-O-glucoside glucosyltransferase. . . . . . . . . . . . . 1792.4.1.240 flavonol-3-O-glycoside glucosyltransferase . . . . . . . . . . . . . 1822.3.1.173 flavonol-3-O-triglucoside O-coumaroyltransferase . . . . . . . . . 722.4.1.243 6G-fructosyltransferase . . . . . . . . . . . . . . . . . . . . . 1962.6.1.79 glutamate-prephenate aminotransferase . . . . . . . . . . . . . . 2382.1.1.156 glycine/sarcosine N-methyltransferase. . . . . . . . . . . . . . . 122.1.1.162 glycine/sarcosine/dimethylglycine N-methyltransferase . . . . . . . 512.7.1.159 inositol-1,3,4-trisphosphate 5/6-kinase . . . . . . . . . . . . . . 2792.7.1.158 inositol-pentakisphosphate 2-kinase . . . . . . . . . . . . . . . 2722.1.1.154 isoliquiritigenin 2’-O-methyltransferase . . . . . . . . . . . . . . 42.4.1.234 kaempferol 3-O-galactosyltransferase . . . . . . . . . . . . . . . 1532.1.1.155 kaempferol 4’-O-methyltransferase . . . . . . . . . . . . . . . . 82.3.1.179 b-ketoacyl-acyl-carrier-protein synthase II . . . . . . . . . . . . 902.3.1.180 b-ketoacyl-acyl-carrier-protein synthase III . . . . . . . . . . . . 992.5.1.69 lavandulyl diphosphate synthase . . . . . . . . . . . . . . . . . 2272.5.1.71 leachianone-G 2’’-dimethylallyltransferase . . . . . . . . . . . . . 232

XIII

2.7.7.63 lipoate-protein ligase . . . . . . . . . . . . . . . . . . . . . 3202.3.1.181 lipoyl(octanoyl) transferase . . . . . . . . . . . . . . . . . . 1272.1.1.158 7-methylxanthosine synthase . . . . . . . . . . . . . . . . . . 252.5.1.66 N2-(2-carboxyethyl)arginine synthase . . . . . . . . . . . . . . 2142.5.1.70 naringenin 8-dimethylallyltransferase . . . . . . . . . . . . . . 2292.4.1.242 NDP-glucose-starch glucosyltransferase . . . . . . . . . . . . . 1882.6.1.80 nicotianamine aminotransferase . . . . . . . . . . . . . . . . 2422.7.10.2 non-specific protein-tyrosine kinase . . . . . . . . . . . . . . . 4412.3.1.174 3-oxoadipyl-CoA thiolase . . . . . . . . . . . . . . . . . . . 742.3.1.183 phosphinothricin acetyltransferase . . . . . . . . . . . . . . . 1342.7.9.5 phosphoglucan, water dikinase . . . . . . . . . . . . . . . . . 3392.5.1.65 O-phosphoserine sulfhydrylase . . . . . . . . . . . . . . . . . 2072.7.1.160 2’-phosphotransferase . . . . . . . . . . . . . . . . . . . . . 2872.3.1.176 propanoyl-CoA C-acyltransferase . . . . . . . . . . . . . . . . 812.7.2.15 propionate kinase . . . . . . . . . . . . . . . . . . . . . . . 2962.6.1.82 putrescine aminotransferase . . . . . . . . . . . . . . . . . . 2502.6.99.2 pyridoxine 5’-phosphate synthase . . . . . . . . . . . . . . . . 2642.7.10.1 receptor protein-tyrosine kinase . . . . . . . . . . . . . . . . 3412.7.4.23 ribose 1,5-bisphosphate phosphokinase . . . . . . . . . . . . . 3142.1.1.157 sarcosine/dimethylglycine N-methyltransferase . . . . . . . . . . 192.7.8.27 sphingomyelin synthase . . . . . . . . . . . . . . . . . . . . 3322.6.1.81 succinylornithine transaminase . . . . . . . . . . . . . . . . . 2442.1.1.159 theobromine synthase . . . . . . . . . . . . . . . . . . . . . 312.7.4.22 UMP kinase . . . . . . . . . . . . . . . . . . . . . . . . . 2992.7.7.64 UTP-monosaccharide-1-phosphate uridylyltransferase . . . . . . . 3262.1.1.153 vitexin 2’’-O-rhamnoside 7-O-methyltransferase . . . . . . . . . 1

XIV

Index of Recommended Enzyme Names

Description of Data Fields

All information except the nomenclature of the enzymes (which is based on therecommendations of theNomenclatureCommittee of IUBMB (InternationalUn-ion of Biochemistry andMolecular Biology) and IUPAC (InternationalUnion ofPure andAppliedChemistry) is extracted fromoriginal literature (or reviews forvery well characterized enzymes). The quality and reliability of the data dependson the method of determination, and for older literature on the techniques avail-able at that time. This is especially true for the fieldsMolecular Weight and Sub-units.The general structure of the fields is: Information – Organism – Commentary –LiteratureThe information can be found in the form of numerical values (temperature, pH,Km etc.) or as text (cofactors, inhibitors etc.).Sometimes data are classified asAdditional Information. Here youmay find datathat cannot be recalculated to the units required for a field or also general infor-mationbeing valid for all values. For example, for Inhibitors,Additional Informa-tionmay contain a list of compounds that are not inhibitory.The detailed structure and contents of each field is described below. If one ofthese fields is missing for a particular enzyme, this means that for this field, nodata are available.

1 Nomenclature

EC numberThe number is as given by the IUBMB, classes of enzymes and subclassesdefined according to the reaction catalyzed.

Systematic nameThis is the name as given by the IUBMB/IUPAC Nomenclature Committee

Recommended nameThis is the name as given by the IUBMB/IUPAC Nomenclature Committee

SynonymsSynonyms which are found in other databases or in the literature, abbrevia-tions, names of commercially available products. If identical names are fre-quently used for different enzymes, these will bementioned here, cross refer-ences are given. If another EC number has been included in this entry, it ismentioned here.

XV

CAS registry numberThe majority of enzymes have a single chemical abstract (CAS) number.Some have no number at all, some have two or more numbers. Sometimestwo enzymes share a common number. When this occurs, it is mentioned inthe commentary.

2 Source Organism

For listing organisms their systematic name is preferred. If these are notmen-tioned in the literature, the names from the respective literature are used. Forexample if an enzyme fromyeast is describedwithout being specified further,yeast will be the entry. This field defines the code numbers for the organismsin which the enzyme with the respective EC number is found. These codenumbers (form <_>) are displayed together with each entry in all fields ofBRENDAwhere organism-specific information is given.

3 Reaction and Specificity

Catalyzed reactionThe reaction as defined by the IUBMB. The commentary gives informationon the mechanism, the stereochemistry, or on thermodynamic data of thereaction.

Reaction typeAccording to the enzyme class a type can be attributed. These can be oxida-tion, reduction, elimination, addition, or a name (e.g. Knorr reaction)

Natural substrates and productsThese are substrates and products which are metabolized in vivo. A naturalsubstrate is only given if it is mentioned in the literature. The commentarygives information on the pathways for which this enzyme is important. If theenzyme is induced by a specific compound or growth conditions, this will beincluded in the commentary. In Additional information you will find com-ments on the metabolic role, sometimes only assumptions can be found inthe references or the natural substrates are unknown.In the listings, each natural substrate (indicated by a bold S) is followed by itsrespective product (indicated by aboldP). Products are givenwith organismsand references included only if the respective authors were able to demon-strate the formation of the specific product. If only the disappearance of thesubstrate was observed, the product is included without organisms of refer-ences. In cases with unclear product formation only a ? as a dummy is given.

Substrates and productsAll natural or synthetic substrates are listed (not in stoichiometric quanti-ties). The commentary gives information on the reversibility of the reaction,

XVI


on isomers accepted as substrates and it compares the efficiencyof substrates.If a specific substrate is accepted by only one of several isozymes, this will bestated here.The field Additional Information summarizes compounds that are not ac-cepted as substrates or general comments which are valid for all substrates.In the listings, each substrate (indicated by a bold S) is followed by its respec-tive product (indicated by a bold P). Products are given with organisms andreferences included if the respective authors demonstrated the formation ofthe specific product. If only the disappearance of the substrate was observed,the product will be included without organisms or references. In cases withunclear product formation only a ? as a dummy is given.

InhibitorsCompounds found to be inhibitory are listed. The commentary may explainexperimental conditions, the concentrationyielding a specific degree of inhi-bition or the inhibition constant. If a substance is activating at a specific con-centration but inhibiting at a higher or lower value, the commentary will ex-plain this.

Cofactors, prosthetic groupsThis field contains cofactors which participate in the reaction but are notbound to the enzyme, and prosthetic groups being tightly bound. The com-mentary explains the function or, if known, the stereochemistry, or whetherthe cofactor can be replaced by a similar compound with higher or lower effi-ciency.

Activating CompoundsThis field lists compounds with a positive effect on the activity. The enzymemay be inactive in the absence of certain compounds or may require activat-ing molecules like sulfhydryl compounds, chelating agents, or lipids. If a sub-stance is activating at a specific concentration but inhibiting at a higher orlower value, the commentary will explain this.

Metals, ionsThis field lists all metals or ions that have activating effects. The commentaryexplains the role each of the cited metal has, being either bound e.g. as Fe-Scenters or being required in solution. If an ionplays a dual role, activating at acertain concentration but inhibiting at a higher or lower concentration, thiswill be given in the commentary.

Turnover number (min-1)The kcat is given in the unit min-1. The commentary lists the names of thesubstrates, sometimeswith information on the reaction conditions or the typeof reaction if the enzyme is capable of catalyzing different reactions with asingle substrate. For cases where it is impossible to give the turnover numberin the defined unit (e.g., substrates without a defined molecular weight, or anundefined amount of protein) this is summarized inAdditional Information.

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Specific activity (U/mg)The unit is micromol/minute/milligram of protein. The commentary maycontain information on specific assay conditions or if another than the natur-al substrate was used in the assay. Entries in Additional Information are in-cluded if the units of the activity aremissing in the literature or are not calcul-able to the obligatory unit. Information on literature with a detailed descrip-tion of the assay method may also be found.

Km-Value (mM)The unit is mM. Each value is connected to a substrate name. The commen-tary gives, if available, information on specific reaction condition, isozymesor presence of activators. The references for values which cannot be ex-pressed in mM (e.g. for macromolecular, not precisely defined substrates)are given in Additional Information. In this field we also cite literature withdetailed kinetic analyses.

Ki-Value (mM)The unit of the inhibition constant is mM. Each value is connected to an in-hibitor name. The commentary gives, if available, the type of inhibition (e.g.competitive, non-competitive) and the reaction conditions (pH-value andthe temperature). Values which cannot be expressed in the requested unitand references for detailed inhibition studies are summerized under Addi-tional information.

pH-OptimumThe value is given to one decimal place. The commentary may contain infor-mation on specific assay conditions, such as temperature, presence of activa-tors or if this optimum is valid for only one of several isozymes. If the enzymehas a second optimum, this will be mentioned here.

pH-RangeMostly given as a range e.g. 4.0–7.0with an added commentary explaining theactivity in this range. Sometimes, not a range but a single value indicating theupper or lower limit of enzyme activity is given. In this case, the commentaryis obligatory.

Temperature optimum (�C)Sometimes, if no temperature optimum is found in the literature, the tempera-ture of the assay is given instead. This is alwaysmentioned in the commentary.

Temperature range (�C)This is the range over which the enzyme is active. The commentary may givethe percentage of activity at the outer limits. Also commentaries on specificassay conditions, additives etc.

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4 Enzyme Structure

Molecular weightThis field gives the molecular weight of the holoenzyme. For monomeric en-zymes it is identical to the value given for subunits. As the accuracy dependson the method of determination this is given in the commentary if providedin the literature. Some enzymes are only active asmultienzyme complexes forwhich the names and/or ECnumbers of all participating enzymes are given inthe commentary.

SubunitsThe tertiary structure of the active species is described. The enzyme can beactive as a monomer a dimer, trimer and so on. The stoichiometry of subunitcomposition is given. Some enzymes can be active in more than one state ofcomplexationwith differing effectivities. The analytical method is included.

Posttranslational modificationsThe main entries in this field may be proteolytic modification, or side-chainmodification, or no modification. The commentary will give details of themodifications e.g.:– proteolytic modification <1> (<1>, propeptide Name) [1];– side-chain modification <2> (<2>, N-glycosylated, 12%mannose) [2];– nomodification [3]

5 Isolation / Preparation / Mutation / Application

Source / tissueFormulticellular organisms, the tissue used for isolation of the enzyme or thetissue inwhich the enzyme is present is given. Cell-lines may also be a sourceof enzymes.

LocalizationThe subcellular localization is described. Typical entries are: cytoplasm, nu-cleus, extracellular, membrane.

PurificationThe field consists of an organism and a reference. Only references with a de-tailed description of the purification procedure are cited.

RenaturationCommentary on denaturant or renaturation procedure.

CrystallizationThe literature is cited which describes the procedure of crystallization, or theX-ray structure.

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CloningLists of organisms and references, sometimes a commentary about expres-sion or gene structure.

EngineeringThe properties of modified proteins are described.

ApplicationActual or possible applications in the fields of pharmacology, medicine, syn-thesis, analysis, agriculture, nutrition are described.

6 Stability

pH-StabilityThis field can either give a range in which the enzyme is stable or a singlevalue. In the latter case the commentary is obligatory and explains the condi-tions and stability at this value.

Temperature stabilityThis field can either give a range in which the enzyme is stable or a singlevalue. In the latter case the commentary is obligatory and explains the condi-tions and stability at this value.

Oxidation stabilityStability in the presence of oxidizing agents, e.g. O2, H2O2, especially impor-tant for enzymes which are only active under anaerobic conditions.

Organic solvent stabilityThe stability in the presence of organic solvents is described.

General stability informationThis field summarizes general information on stability, e.g., increased stabi-lity of immobilized enzymes, stabilizationby SH-reagents, detergents, glycer-ol or albumins etc.

Storage stabilityStorage conditions and reported stability or loss of activity during storage.

ReferencesAuthors, Title, Journal, Volume, Pages, Year.

XX


Vitexin 2’’-O-rhamnoside7-O-methyltransferase

2.1.1.153

1 Nomenclature

EC number2.1.1.153

Systematic nameS-adenosyl-l-methionine:vitexin-2’’-O-b-l-rhamnoside 7-O-methyltransfer-ase

Recommended namevitexin 2’’-O-rhamnoside 7-O-methyltransferase

SynonymsAdoMet:vitexin 2’’-O-rhamnoside 7-O-methyltransferase <1> [1]FMT <1> [2]S-adenosyl-l-methionine:vitexin 2’’-O-rhamnoside 7-O-methyltransferase<1> [2]methyltransferase, vitexin 2’’-O-rhamnoside 7-O- <1> [1]

CAS registry number90698-29-6

2 Source Organism

<1> Avena sativa (no sequence specified) [1, 2]


Catalyzed reactionS-adenosyl-l-methionine + vitexin 2’’-O-b-l-rhamnoside = S-adenosyl-l-homocysteine + 7-O-methylvitexin 2’’-O-b-l-rhamnoside (<1> the flavo-noids vitexin and isovitexin 2’’-O-arabinoside do not act as substrates forthe enzyme from oats, Avena sativa, kinetic mechanism, mono-iso Theorell-Chance mechanism [1])

Reaction typetransfer of methyl group

Natural substrates and productsS S-adenosyl-l-methionine + vitexin 2’’-O-b-l-rhamnoside <1> (<1> flavo-

noid biosynthesis, final enzyme of the vitexin branch of the pathway [2];

1

<1> last step in the biosynthetic pathway to the flavonoid 7-O-methylvi-texin 2’’-O-rhamnoside [1]) (Reversibility: ?) [1, 2]

P S-adenosyl-l-homocysteine + 7-O-methylvitexin 2’’-O-b-l-rhamnoside

Substrates and productsS S-adenosyl-l-methionine + apigenin <1> (<1> 5-10% of the rate with

vitexin 2’’-O-rhamnoside as substrate [1]) (Reversibility: ?) [1]P S-adenosyl-l-homocysteine + 7-O-methylapigeninS S-adenosyl-l-methionine + vitexin 2’’-O-b-l-rhamnoside <1> (<1> flavo-

noid biosynthesis, final enzyme of the vitexin branch of the pathway [2];<1> last step in the biosynthetic pathway to the flavonoid 7-O-methylvi-texin 2’’-O-rhamnoside [1]; <1> catalyzes the transfer of the methyl groupof S-adenosyl-l-methionine to the A-ring 7-hydroxyl group of vitexin 2’’-O-rhamnoside, very high substrate specificity, mono-iso Theorell-Chancemechanism with the nucleotide substrate binding before the flavonoid [1];<1> FMT specifically catalyzes the transfer of a methyl group to the 7-hydroxyl group of vitexin 2’’-O-rhamnoside [2]) (Reversibility: ?) [1, 2]

P S-adenosyl-l-homocysteine + 7-O-methylvitexin 2’’-O-b-l-rhamnosideS Additional information <1> (<1> not: caffeic acid, naringenin, vitexin,

isovitexin 2’’-O-arabinoside [1]) (Reversibility: ?) [1]P ?

Inhibitors7-O-methylvitexin <1> (<1> competitive inhibition [1]) [1]7-O-methylvitexin 2’’-O-b-l-rhamnoside <1> (<1> product inhibition, ki-netics [1]) [1]S-adenosyl-l-homocysteine <1> (<1> strong product inhibition, kinetics[1]) [1]vitexin <1> (<1> competitive inhibition [1]) [1]Additional information <1> (<1> not inhibited by Mg2+ or 2-mercaptoetha-nol [1]) [1]

Metals, ionsphosphate <1> (<1> the highest activity is obtained in 0.1-0.2 M phosphatebuffer, at lower ionic strength the activity drops drastically [1]) [1]Additional information <1> (<1> not activated by Mg2+ or 2-mercaptoetha-nol [1]) [1]

Specific activity (U/mg)Additional information <1> [1]

Km-Value (mM)0.0016 <1> (S-adenosyl-l-methionine, <1> pH 7.5, 30�C [1]) [1]0.015 <1> (vitexin 2’’-O-b-l-rhamnoside, <1> pH 7.5, 30�C [1]) [1]Additional information <1> (<1> kinetic mechanism, mono-iso Theorell-Chance mechanism with the nucleotide substrate binding before the flavo-noid [1]) [1]

Ki-Value (mM)Additional information <1> [1]

2

Vitexin 20 0-O-rhamnoside 7-O-methyltransferase 2.1.1.153

pH-Optimum7.5 <1> [1]

pH-Range6.4-8.6 <1> (<1> 50% of the maximum activity at pH 6.4 and 8.6 [1]) [1]

Temperature optimum (�C)30 <1> (<1> assay at [1,2]) [1, 2]

4 Enzyme Structure

Molecular weight52000 <1> (<1> gel filtration [1]) [1]

5 Isolation/Preparation/Mutation/Application

Source/tissueleaf <1> (<1> primary leaves [1]; <1> primary leaves, tissue-specific activityin different stages of leaf growth, FMT is located in the mesophyll [2]) [1, 2]Additional information <1> (<1> FMT activity profile as a function of plantage [2]) [2]

Purification<1> (180fold) [1]

6 Stability

General stability information<1>, 2-mercaptoethanol stabilizes during purification procedures or storage[1]

Storage stability<1>, -20�C, purified enzyme, 10mM 2-mercaptoethanol, 50% glycerol, 1year, 30-40% loss of activity [1]

References

[1] Knogge, W.; Weissenboeck, G.: Purification, characterization, and kineticmechanism of S-adenosyl-l-methionine: vitexin 2“-O-rhamnoside 7-O-methyltransferase of Avena sativa L. Eur. J. Biochem., 140, 113-118 (1984)

[2] Knogge, W.; Weissenboeck, G.: Tissue-distribution of secondary phenolicbiosynthesis in developing primary leaves of Avena sativa L.. Planta, 167,196-205 (1986)

3

2.1.1.153 Vitexin 20 0-O-rhamnoside 7-O-methyltransferase

Isoliquiritigenin 2’-O-methyltransferase 2.1.1.154

1 Nomenclature

EC number2.1.1.154

Systematic nameS-adenosyl-l-methionine:isoliquiritigenin 2’-O-methyltransferase

Recommended nameisoliquiritigenin 2’-O-methyltransferase

SynonymsCHMT <1> [1, 2]OMT <1> [3]chalcone OMT <1> [2]isoliquiritigenin 2’-O-methyltransferasechalcone <1> [3]


2 Source Organism

<1> Medicago sativa (no sequence specified) [1, 2, 3]<2> no activity in Glycyrrhiza echinata [1]


Catalyzed reactionS-adenosyl-l-methionine + isoliquiritigenin = S-adenosyl-l-homocysteine +2’-O-methylisoliquiritigenin (<1> sequential Bi Bi mechanism [2])

Reaction typemethyl group transfer

Natural substrates and productsS S-adenosyl-l-methionine + isoliquiritigenin <1> (<1> the product of the

reaction, 2-O-methylisoliquiritigenin, is the most potent inducer of nodu-lation genes of Rhizobium meliloti, the symbiont of Medicago sativawhich forms nitrogen-fixing nodules [1]) (Reversibility: ?) [1]

P S-adenosyl-l-homocysteine + 2’-O-methylisoliquiritigenin

4

S Additional information <1> (<1> the enzyme is specifically involved inthe biosynthesis of an inducer of Rhizobium meliloti nodulation genes[3]) (Reversibility: ?) [3]

P ?

Substrates and productsS S-adenosyl-l-methionine + 2’,4’-dihydroxy-4-methoxychalcone <1> (<1>

77% of the activity with isoliquiritigenin [2]) (Reversibility: ?) [2]P S-adenosyl-l-homocysteine + 4’-hydroxy-2’,4-dimethoxychalconeS S-adenosyl-l-methionine + 4’,7-dihydroxyflavanone <1> (<1> 32% of the

activity with isoliquiritigenin [2]) (Reversibility: ?) [2]P S-adenosyl-l-homocysteine + ?S S-adenosyl-l-methionine + isoliquiritigenin <1> (<1> the product of the

reaction, 2-O-methylisoliquiritigenin, is the most potent inducer of nodu-lation genes of Rhizobium meliloti, the symbiont of Medicago sativawhich forms nitrogen-fixing nodules [1]) (Reversibility: ?) [1, 2]

P S-adenosyl-l-homocysteine + 2’-O-methylisoliquiritigeninS Additional information <1> (<1> the enzyme is specifically involved in

the biosynthesis of an inducer of Rhizobium meliloti nodulation genes[3]; <1> no activity towards naringenin chalcone, caffeic acid or daidzein[2]) (Reversibility: ?) [2, 3]

P ?

Inhibitors4,4’-dihydroxy-2’-methoxychalcone <1> (<1> noncompetitive [2]) [2]Co2+ <1> (<1> 1mM, 22% inhibition [2]) [2]Cu2+ <1> (<1> 1mM, 12% inhibition [2]) [2]Fe2+ <1> (<1> 1mM, 44% inhibition [2]) [2]S-adenosyl-l-homocysteine <1> (<1> competitive with respect to S-adeno-syl-l-methionine [2]) [2]Zn2+ <1> (<1> 1mM, 45% inhibition [2]) [2]

Specific activity (U/mg)0.13 <1> [2]

Km-Value (mM)2.2 <1> (isoliquiritigenin) [2]17.7 <1> (S-adenosyl-l-methionine) [2]

Ki-Value (mM)0.0022 <1> (S-adenosyl-l-homocysteine) [2]0.0652 <1> (4,4’-dihydroxy-2’-methoxychalcone) [2]

pH-Optimum9 <1> [2]

5

2.1.1.154 Isoliquiritigenin 2’-O-methyltransferase

4 Enzyme Structure

Molecular weight57000 <1> (<1> gel filtration [2]) [2]

Subunitsmonomer <1> (<1> 1 * 43000, SDS-PAGE [2]) [2]


Source/tissuecell culture <1> (<1> rapid and transient increase in extractable activitiesafter treatment with yeast extract [1]) [1, 2, 3]root <1> (<1> of seedlings [1]; <1> enzyme activity increases during earlystages of seedling development and is predomonantly located in the root [2];<1> regardless of plant age [3]) [1, 2, 3]root nodule <1> (<1> regardless of plant age, expression to low extent [3])[3]seedling <1> (<1> enzyme activity increases during early stages of seedlingdevelopment and is predomonantly located in the root [2]; <1> root, not inshoot [1]) [1, 2]

Localizationsoluble <1> (<1> 98% of the activity is in the soluble fraction [2]) [2]

Purification<1> [2]

Cloning<1> [3]<1> (expression in Escherichia coli) [1]

6 Stability

Temperature stability4 <1> (<1> half-life: 3-4 days [2]) [2]

General stability information<1>, stabilized in presence of 5mM EDTA [2]

Storage stability<1>, -80�C, 12% loss of activity after 1.5 months [2]<1>, 4�C, half-life: 3-4 days [2]

6

Isoliquiritigenin 2’-O-methyltransferase 2.1.1.154

References

[1] Ichimura, M.; Furuno, T.; Takahashi, T.; Dixon, R.A.; Ayabe, S.: Enzymic O-methylation of isoliquiritigenin and licodione in alfalfa and licorice cultures.Phytochemistry, 44, 991-995 (1997)

[2] Maxwell, C.A.; Edwards, R.; Dixon, R.A.: Identification, purification, andcharacterization of S-adenosyl-l-methionine: isoliquiritigenin 2’-O-methyl-transferase from alfalfa (Medicago sativa L.). Arch. Biochem. Biophys., 293,158-166 (1992)

[3] Maxwell, C.A.; Harrison, M.J.; Dixon, R.A.: Molecular characterization andexpression of alfalfa isoliquiritigenin 2’-O-methyltransferase, an enzyme spe-cifically involved in the biosynthesis of an inducer of Rhizobium melilotinodulation genes. Plant J., 4, 971-981 (1993)

7

2.1.1.154 Isoliquiritigenin 2’-O-methyltransferase

Kaempferol 4’-O-methyltransferase 2.1.1.155

1 Nomenclature

EC number2.1.1.155

Systematic nameS-adenosyl-l-methionine:kaempferol 4’-O-methyltransferase

Recommended namekaempferol 4’-O-methyltransferase

Synonyms4’OMT <1> [2]CrOMT6 <1> [2]F 4’-OMT <2> [1]S-adenosyl-l-methionine:flavonoid 4’-O-methyltransferase <2> [1]flavonoid O-methyltransferase <2> [1]flavonoid methyltransferase <2> [1]methyltransferase, flavonoid <2> [1]


2 Source Organism

<1> Catharanthus roseus (no sequence specified) [2]<2> Dianthus caryophyllus (no sequence specified) [1]


Catalyzed reactionS-adenosyl-l-methionine + kaempferol = S-adenosyl-l-homocysteine +kaempferide (<2> the enzyme acts on the hydroxy group in the 4’-positionof some flavones, flavanones and isoflavones, kaempferol, apigenin andkaempferol triglucoside are substrates, as is genistein, which reacts moreslowly, compounds with an hydroxy group in the 3’ and 4’ positions, such asquercetin and eriodictyol, do not act as substrates, similar to EC 2.1.1.75,apigenin 4’-O-methyltransferase and EC 2.1.1.83, 3,7-dimethylquercitin 4’-O-methyltransferase, ping-pong mechanism excluding the formation of a tern-ary complex [1])

8

Reaction typetransfer of methyl group

Natural substrates and productsS Additional information <2> (<2> the role of F 4’-OMT is mainly defen-

sive against parasites, rather than structural [1]) (Reversibility: ?) [1]P ?

Substrates and productsS S-adenosyl-l-methionine + 4’-hydroxyflavanone <2> (Reversibility: ?) [1]P S-adenosyl-l-homocysteine + 4’-methoxyflavanoneS S-adenosyl-l-methionine + a flavonoid <1, 2> (<1> 4’-OMT methylates

the position 4’ in the B-ring of flavonoids, uses flavonoids methylated inthe 3’-position of the B-ring to synthesize a 3’,4’-methylated product, amethylated flavanone, homoeriodictyol, is the best substrate [2]; <2>F 4’-OMT specifically methylates the hydroxy substituent in 4’-position ofthe flavones, flavanones and isoflavones in the presence of S-adenosyl-l-methionine, enzyme affinity for the substrate and catalytic efficiency de-creases in the following order: 4’-hydroxyflavones, 4’-hydroxyflavanones,4’-hydroxyisoflavones, ping-pong mechanism, which excludes the forma-tion of a ternary complex [1]) (Reversibility: ?) [1, 2]

P S-adenosyl-l-homocysteine + a 4’-methoxyflavonoidS S-adenosyl-l-methionine + apigenin <2> (Reversibility: ?) [1]P S-adenosyl-l-homocysteine + acacetin (<2> 4’-methoxyapigenin [1])S S-adenosyl-l-methionine + chrysoeriol <1> (<1> good substrate [2])

(Reversibility: ?) [2]P S-adenosyl-l-homocysteine + 4’-methoxychrysoeriolS S-adenosyl-l-methionine + eriodictyol <1> (<1> lower activity than with

homoeriodictyol, isorhamnetin or chrysoeriol [2]) (Reversibility: ?) [2]P S-adenosyl-l-homocysteine + 4’-methoxyeriodictyolS S-adenosyl-l-methionine + genistein <2> (Reversibility: ?) [1]P S-adenosyl-l-homocysteine + biochanin A (<2> 4’-methoxygenistein [1])S S-adenosyl-l-methionine + homoeriodictyol <1> (<1> best substrate [2])

(Reversibility: ?) [2]P S-adenosyl-l-homocysteine + 4’-methoxyhomoeriodictyolS S-adenosyl-l-methionine + isorhamnetin <1> (<1> good substrate [2])

(Reversibility: ?) [2]P S-adenosyl-l-homocysteine + 4’-methoxyisorhamnetinS S-adenosyl-l-methionine + kaempferol <1, 2> (<1> lower activity than

with homoeriodictyol, isorhamnetin or chrysoeriol [2]) (Reversibility: ?)[1, 2]

P S-adenosyl-l-homocysteine + kaempferideS S-adenosyl-l-methionine + kaempferol 3-O-b-d-glucopyranosyl-1,4-O-a-

l-rhamnopyranosyl-1,2-b-d-glucopyranoside <2> (Reversibility: ?) [1]P S-adenosyl-l-homocysteine + 4’-O-methylkaempferol 3-O-b-d-glucopyra-

nosyl-1,4-O-a-l-rhamnopyranosyl-1,2-b-d-glucopyranosideS S-adenosyl-l-methionine + quercetin <1> (<1> lower activity than with

homoeriodictyol, isorhamnetin or chrysoeriol [2]) (Reversibility: ?) [2]

9

2.1.1.155 Kaempferol 4’-O-methyltransferase

P S-adenosyl-l-homocysteine + 4’-methoxyquercetinS Additional information <1, 2> (<2> the role of F 4’-OMT is mainly defen-

sive against parasites, rather than structural [1]; <2> not: 4-hydroxyben-zoic acid, gallic acid, p-coumaric acid, caffeic acid, caffeoyl-CoA, querce-tin, rutin, luteolin, eriodictyol, 3’,4’,7’-trihydroxyisoflavone, datiscetin [1];<1> not: naringenin, pentahydroxyflavanone, hesperetin, myricetin, 7,3’-O-dimethylquercetin, 7-O-methylquercetin, syringetin, apigenin, luteolin,tricetin, velutin, dihydrokaempferol, dihydroquercetin, dihydromyricetin,3’-O-methyl-dihydroquercetin [2]) (Reversibility: ?) [1, 2]

P ?

InhibitorsCa2+ <2> (<2> 10mM, 19% inhibition [1]) [1]iodoacetamide <2> (<2> 1mM, 60% inhibition [1]) [1]Mg2+ <2> (<2> 10mM, 27% inhibition [1]) [1]Mn2+ <2> (<2> 1mM: 21% inhibition, 10mM: 57% inhibition [1]) [1]phenylmercuriacetate <2> (<2> 1mM, 80% inhibition [1]) [1]S-adenosyl-l-homocysteine <2> (<2> competitive, inhibition kinetics [1])[1]

Activating compoundsAdditional information <2> (<2> activity is increased, in both in vitro andin vivo carnation tissues, by the inoculation with Fusarium oxysporum f.sp. dianthi [1]) [1]

Metals, ionsAdditional information <2> (<2> no divalent metal ion requirement [1]) [1]

Specific activity (U/mg)70.5 <2> (<2> pH 7, 25�C [1]) [1]

Km-Value (mM)0.0017 <2> (kaempferol, <2> pH 7, 25�C [1]) [1]0.0033 <2> (apigenin, <2> pH 7, 25�C [1]) [1]0.011 <2> (4’-hydroxyflavanone, <2> pH 7, 25�C [1]) [1]0.0735 <2> (genistein, <2> pH 7, 25�C [1]) [1]Additional information <2> (<2> kinetic mechanism [1]) [1]

Ki-Value (mM)0.012 <2> (S-adenosyl-l-homocysteine, <2> pH 7, 25�C [1]) [1]

pH-Optimum6.9-7 <2> [1]7.5 <1> (<1> assay at [2]) [2]

pH-Range5-8.5 <2> (<2> 50% of maximum activity at pH 5.5 and 8.5, 4% of maximumactivity at pH 5 [1]) [1]

Temperature optimum (�C)25 <2> (<2> assay at [1]) [1]

10

Kaempferol 4’-O-methyltransferase 2.1.1.155

4 Enzyme Structure

Molecular weight43000-45000 <2> (<2> gel filtration, native PAGE [1]) [1]

Subunitsmonomer <2> [1]


Source/tissuecallus <2> [1]cell suspension culture <1> [2]stem <2> [1]

Localizationsoluble <1> (<1> recombinant enzyme [2]) [2]

Purification<1> (recombinant enzyme) [2]<2> (1399fold) [1]

Cloning<1> (CrOMT6 gene, expression in Escherichia coli, gene structure) [2]

6 Stability

pH-Stability5-8.5 <2> (<2> 50% of maximum activity at pH 5.5 and 8.5, 4% of maximumactivity at pH 5 [1]) [1]

Storage stability<2>, -20�C, 2 weeks, 50% loss of activity [1]

References

[1] Curir, P.; Lanzotti, V.; Dolci, M.; Dolci, P.; Pasini, C.; Tollin, G.: Purificationand properties of a new S-adenosyl-l-methionine:flavonoid 4’-O-methyl-transferase from carnation (Dianthus caryophyllus L.). Eur. J. Biochem.,270, 3422-3431 (2003)

[2] Schroeder, G.; Wehinger, E.; Lukacin, R.; Wellmann, F.; Seefelder, W.; Schwab,W.; Schroeder, J.: Flavonoid methylation: a novel 4’-O-methyltransferasefrom Catharanthus roseus, and evidence that partially methylated flavanonesare substrates of four different flavonoid dioxygenases. Phytochemistry, 65,1085-1094 (2004)

11

2.1.1.155 Kaempferol 4’-O-methyltransferase

Glycine/sarcosine N-methyltransferase 2.1.1.156

1 Nomenclature

EC number2.1.1.156

Systematic nameS-adenosyl-l-methionine:sarcosine N-methyltransferase

Recommended nameglycine/sarcosine N-methyltransferase

SynonymsGSMT <2, 3, 4, 5> [1, 2, 3]glycine sarcosine N-methyltransferase <2, 6> [1, 4]glycine sarcosine methyltransferase <3, 4> [2]


2 Source Organism

<1> Aphanothece halophytica (no sequence specified) [5]<2> Ectothiorhodospira halochloris (no sequence specified) [1]<3> Ectothiorhodospira halochloris (UNIPROT accession number: Q9KJ22) [2]<4> Actinopolyspora halophila (UNIPROT accession number: Q9KJ20) [2]<5> Aphanothece halophytica (UNIPROT accession number: Q83WC4) (<5>

PKG Ib [3]) [3]<6> Synechococcus sp. WH8102 (no sequence specified) [4]


Catalyzed reactionS-adenosyl-l-methionine + glycine = S-adenosyl-l-homocysteine + sarcosineS-adenosyl-l-methionine + sarcosine = S-adenosyl-l-homocysteine + N,N-dimethylglycine

Natural substrates and productsS S-adenosyl-l-methionine + N-methylglycine <1, 6> (<1,6> synthesis of

the compatible solute betaine de novo through the methylation of glycine,sarcosine and dimethylglycine with the methyl group from S-adenosyl-methionine [4,5]) (Reversibility: ?) [4, 5]

12

P S-adenosyl-l-homocysteine + N,N-dimethylglycineS S-adenosyl-l-methionine + glycine <2, 3, 4, 5> (Reversibility: ?) [1, 2, 3]P S-adenosyl-l-homocysteine + sarcosine (<2> i.e. 2-methylglycine [1])S S-adenosyl-l-methionine + glycine <1, 6> (<1,6> synthesis of the compa-

tible solute betaine de novo through the methylation of glycine, sarcosineand dimethylglycine with the methyl group from S-adenosylmethionine[4,5]) (Reversibility: ?) [4, 5]

P S-adenosyl-l-homocysteine + N-methylglycineS S-adenosyl-l-methionine + sarcosine <2, 3, 4, 5> (Reversibility: ?) [1, 2,

3]P S-adenosyl-l-homocysteine + N,N-dimethylglycineS Additional information <2, 3, 4, 5> (<3, 4> the enzyme catalyzes the first 2

steps of betaine synthesis from glycine in a 3-step process [2]; <2> the en-zyme catalyzes the first 2 steps of glycine betaine synthesis from glycine ina 3-step process, betaine is required for balancing osmotic pressure underhigh salt living conditions [1]; <5> the enzyme is involved in the alternatebiosynthesis of betaine, which is an important osmoprotectant and issynthesized in response to abiotic stress [3]) (Reversibility: ?) [1, 2, 3]

P ?

Substrates and productsS S-adenosyl-l-methionine + N-methylglycine <1, 6> (<1,6> synthesis of

the compatible solute betaine de novo through the methylation of glycine,sarcosine and dimethylglycine with the methyl group from S-adenosyl-methionine [4,5]) (Reversibility: ?) [4, 5]

P S-adenosyl-l-homocysteine + N,N-dimethylglycineS S-adenosyl-l-methionine + glycine <1, 6> (<1,6> synthesis of the compa-

tible solute betaine de novo through the methylation of glycine, sarcosineand dimethylglycine with the methyl group from S-adenosylmethionine[4,5]) (Reversibility: ?) [4, 5]

P S-adenosyl-l-homocysteine + N-methylglycineS S-adenosyl-l-methionine + glycine <2, 3, 4, 5> (<2> the recombinant en-

zyme from Escherichia coli is 3.3fold less active than the wild-type en-zyme [1]) (Reversibility: ?) [1, 2, 3]

P S-adenosyl-l-homocysteine + sarcosine (<2,3,5> i.e. 2-methylglycine[1,2,3])

S S-adenosyl-l-methionine + sarcosine <2, 3, 4, 5> (<4> i.e. 2-methylgly-cine [2]; <2> the recombinant enzyme from Escherichia coli is 2.5fold lessactive than the wild-type enzyme [1]) (Reversibility: ?) [1, 2, 3]

P S-adenosyl-l-homocysteine + N,N-dimethylglycineS Additional information <2, 3, 4, 5, 6> (<3, 4> the enzyme catalyzes the first

2 steps of betaine synthesis from glycine in a 3-step process [2]; <2> theenzyme catalyzes the first 2 steps of glycine betaine synthesis from glycinein a 3-step process, betaine is required for balancing osmotic pressure un-der high salt living conditions [1]; <5> the enzyme is involved in the alter-nate biosynthesis of betaine, which is an important osmoprotectant and issynthesized in response to abiotic stress [3]; <5> enzyme shows strict

13

2.1.1.156 Glycine/sarcosine N-methyltransferase

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