EnzymesEnzymes

The The proteinprotein catalyst catalyst of lifeof life

Enzymes: The Video Enzymes: The Video ClipClip

Enzyme VocabularyEnzyme Vocabulary

• Enzymes end in Enzymes end in ––asease• MaltMaltasease binds to maltose binds to maltose• LactLactasease binds to lactose binds to lactose• LipLipasease breaks down fat breaks down fat• AmylAmylasease is found in saliva is found in saliva

• Catalyst:Catalyst:• Substance that affects the Substance that affects the raterate of a of a

chemical reaction chemical reaction WITHOUT BEING WITHOUT BEING ALTEREDALTERED

• Because it is not altered, can do same Because it is not altered, can do same thing over, and, over, and, over, and thing over, and, over, and, over, and over…….over…….

• Enzymes are Enzymes are ORGANICORGANIC CATALYSTS CATALYSTS

Enzyme VocabularyEnzyme Vocabulary

• Substrate:Substrate:• The substance upon which The substance upon which

the enzyme reactsthe enzyme reacts

• Active site:Active site:• Site where enzyme binds to Site where enzyme binds to

substratesubstrate

• Denature:Denature:• When enzyme’s shape is When enzyme’s shape is

altered due to:altered due to:• high temp high temp • strong acids or basesstrong acids or bases

How Do Enzymes Work?How Do Enzymes Work?

DEMO

Importance of Enzyme Importance of Enzyme ShapeShape

• Enzymes have Enzymes have specific shapesspecific shapes• This means enzymes are This means enzymes are specificspecific to to

their substratetheir substrate• They will only attach to substrate that They will only attach to substrate that

“fits” their shape“fits” their shape• If shape of enzyme is denatured, will it If shape of enzyme is denatured, will it

be able to bind to its substrate?be able to bind to its substrate?• NONO!!

• TwoTwo things can cause denaturing: things can cause denaturing:• TemperatureTemperature• pHpH

Denaturing or Mutation of Denaturing or Mutation of Enzyme: The Video ClipEnzyme: The Video Clip

Enzyme-Substrate Enzyme-Substrate ComplexComplex

• Formed when enzyme binds to Formed when enzyme binds to substratesubstrate• Very specificVery specific

• Lock and Key Model:Lock and Key Model:• Enzyme-substrate complex often compared Enzyme-substrate complex often compared

to a lock and keyto a lock and key• Active site on enzyme can only “FIT” or Active site on enzyme can only “FIT” or

bind to a bind to a

specific substratespecific substrate• Example: Amylase will bind to starch, but not Example: Amylase will bind to starch, but not

cellulosecellulose

Enzyme-substrate Enzyme-substrate ComplexComplex

The Enzyme Jingle!The Enzyme Jingle!SUNG TO “JINGLE BELLS”!SUNG TO “JINGLE BELLS”!

Shape, Shape, ShapeShape, Shape, ShapeShape, Shape, ShapeShape, Shape, Shape

Enzymes have a shapeEnzymes have a shapeIf active site is denaturedIf active site is denatured

It won’t bind suuu-uuuub-stra-ateIt won’t bind suuu-uuuub-stra-ateShape, shape, shapeShape, shape, shapeShape, shape, shapeShape, shape, shape

Enzymes have a shapeEnzymes have a shapeWrong pH or temperatureWrong pH or temperature

Will affect its shapeWill affect its shape

What affects Enzyme What affects Enzyme Reaction Rates?Reaction Rates?

• Remember, enzymes Remember, enzymes speed speed up reactionsup reactions

• What can affect the rate at What can affect the rate at which enzymes perform?which enzymes perform?•It’s It’s shapeshape!!

•Denaturing affects rateDenaturing affects rate

•The The amountamount of of enzymeenzyme and and substratesubstrate!!

Enzyme shape and Enzyme shape and reaction rate: reaction rate: TemperatureTemperature

• Enzymes have a specific temperature Enzymes have a specific temperature range at which they work bestrange at which they work best• EXEX. Human enzymes work best at 37. Human enzymes work best at 37°°CC

• Temps not in the optimal range will Temps not in the optimal range will cause enzymes to denaturecause enzymes to denature

• Shape is Shape is alteredaltered, so reaction rates are , so reaction rates are SLOWED or stopped altogetherSLOWED or stopped altogether

• Reaction rates will DROP dramatically Reaction rates will DROP dramatically depending on how much denaturing of depending on how much denaturing of enzyme enzyme DEMO

Temperature vs. Temperature vs. Reaction RateReaction Rate

Enzyme shape and Enzyme shape and reaction rate: pHreaction rate: pH

• Enzymes have a specific pH range at Enzymes have a specific pH range at which they work bestwhich they work best• EXEX. Most enzymes work best at pH 7. Most enzymes work best at pH 7• Where in the body would enzymes be Where in the body would enzymes be

optimal at a low (acidic) pH? Why?optimal at a low (acidic) pH? Why?• In stomach. This is because stomach acid has a In stomach. This is because stomach acid has a

low pHlow pH

• pH not in the optimal range will cause pH not in the optimal range will cause enzymes to denatureenzymes to denature

• Shape is Shape is alteredaltered, so reaction rates are , so reaction rates are SLOWED or stopped altogetherSLOWED or stopped altogether

• Reaction rates will DROP dramatically Reaction rates will DROP dramatically depending on how much denaturing of depending on how much denaturing of enzyme enzyme DEMO

pH vs. Reaction RatepH vs. Reaction Rate

Enzyme amount and Enzyme amount and reaction ratereaction rate

• Enzyme rate also depends on the Enzyme rate also depends on the amount of enzyme and substrateamount of enzyme and substrate• Little enzyme, lots o’ substrate:Little enzyme, lots o’ substrate:

•Slower ratesSlower rates•How can we speed up the How can we speed up the rate?rate?•Add more enzyme until max. Add more enzyme until max. rate achieved.rate achieved.

Substrate Concentration Substrate Concentration vs. Reaction Ratevs. Reaction Rate