what you should know from today’s lecture
DESCRIPTION
What you should know from today’s lecture. Examples and chemical basis of the diversity of proteins and their functions. Levels of protein structure and the chemical bonds that stabilize each level. 3-D structure determines biological function. Denaturation. Enzymes and catalysis. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/1.jpg)
What you should know from today’s lecture
• Examples and chemical basis of the diversity of proteins and their functions.
• Levels of protein structure and the chemical bonds that stabilize each level.
• 3-D structure determines biological function.
• Denaturation.
• Enzymes and catalysis.
• Enzyme cofactors, vitamins, and minerals.
• Biochemical pathways.
![Page 2: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/2.jpg)
Function Example
Structural Muscle fiber (myosin)
Rhino horn (keratin)
Hormonal Insulin, leptin, hGH
Binding Antibodies (-globulin), receptors, snake venom
Transport Na+/K+ pump, hemoglobin, HDL
N storage Gluten, zein, albumin
Enzymes/catalytic
Sucrase, amylase, protease, nuclease
Misc. Antifreeze
Infectious Mad cow disease (prion)
The diverse functions of proteins
![Page 3: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/3.jpg)
Fig. 3.16, p. 43
Levels of protein structure
![Page 4: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/4.jpg)
Would you like to:• Reduce human suffering?
• Win a Nobel Prize?
• Become richer than Bill Gates?
• Here’s how:
![Page 5: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/5.jpg)
Why is it so hard to predict protein folding?
• Even a small protein made of just 100 amino acids has 3200 possible backbone configurations.
• The fastest supercomputers can do 1015 calculations per second.
• Even at that speed, it would take 1080 seconds to calculate the 3-dimensional shape of the small protein.
• The universe is only 1020 seconds old.
• A real protein folds in a microsecond (10-6 seconds).
![Page 6: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/6.jpg)
Protein denaturation• Hydrogen bonds are broken,
destroying 3-D structure, and, therefore, protein function
• Denatured proteins are less soluble in water
• Covalent peptide bonds are NOT broken
• Common protein denaturants are gentle heat (100oC or less), solvents such as ethanol, even violent mechanical action such as beating an egg white
• Sometimes reversible, sometimes not
![Page 7: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/7.jpg)
Biochemical reactionsA-P-P-PATP
A-P-P + P + energyADP
substrates(reactants)
products
Rules of thumb:•Chemical reactions proceed spontaneously from few complex molecules to a greater number of less complex molecules; from higher bond energy to lower energy•Making a more complex molecule from simpler substrates requires energy input
![Page 8: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/8.jpg)
Catalysts• Increase the rate of a
chemical reaction
• Do not affect the equilibrium of the reaction
• Participate in the reaction but are not ‘used up’
• Are neither a substrate nor a product of the reaction
• Protein catalysts (enzymes) are exquisitely specific for their substrates and products
• Enzymes typically accelerate reaction rates by thousands or millions of times
![Page 9: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/9.jpg)
The effect of enzymes on chemical reactions
O
OHO
OH
HO
OH
P
OO
HO
OH
HO OH
P1:19
G1P : G6P
![Page 10: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/10.jpg)
How do enzymes work?
Lock-and-keyInduced fit
Sucrose Glucose + FructoseSucrase
![Page 11: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/11.jpg)
Enzyme cofactors (coenzymes)
• Provide a wider range of chemically active ‘functional’ groups than are available in the 20 amino acid ‘R’ groups
• Vitamins
Example: nicotinic acid (niacin) in NADH and NADPH
• MineralsIron (Fe++) in hemoglobin
Magnesium (Mg++) in chlorophyll
![Page 12: What you should know from today’s lecture](https://reader036.vdocuments.us/reader036/viewer/2022081511/56814fac550346895dbd6a9d/html5/thumbnails/12.jpg)
Biochemical pathways