EnzymesEnzymesAS Unit 1AS Unit 1

IntroductionIntroduction

Enzymes as CatalystsEnzymes as Catalysts

Learning ObjectivesLearning Objectives

Describe the structure of enzymesDescribe the structure of enzymes Explain how enzymes act as Explain how enzymes act as

catalystscatalysts Understand the effects of pH, and Understand the effects of pH, and

temperature on enzymestemperature on enzymes

Properties of EnzymesProperties of Enzymes

Enzymes are large protein moleculesEnzymes are large protein molecules They act as biological catalystsThey act as biological catalysts They are globular proteins, with a They are globular proteins, with a

hydrophobic core and hydrophilic outer hydrophobic core and hydrophilic outer amino-acids, so they are usually solubleamino-acids, so they are usually soluble

They have a complex tertiary structure They have a complex tertiary structure which causes them the to fold in a very which causes them the to fold in a very specific way to create an specific way to create an active siteactive site

Enzyme SpecificityEnzyme Specificity

Enzymes react with chemicals either Enzymes react with chemicals either to build up longer polymer chains or to build up longer polymer chains or to break down long chains into small to break down long chains into small sub unitssub units

The chemicals which an enzyme The chemicals which an enzyme reacts with are called substratesreacts with are called substrates

Every enzymes is specific to one Every enzymes is specific to one substrate onlysubstrate only

Builder or BreakerBuilder or Breaker

Enzymes as CatalystsEnzymes as Catalysts

A catalysts speeds up the rate of a A catalysts speeds up the rate of a reaction with out being used up in the reaction with out being used up in the processprocess

Enzymes also reduce the activation Enzymes also reduce the activation energy required for the reaction to energy required for the reaction to take placetake place

Enzymes do this by binding to the Enzymes do this by binding to the substrate at a special active site in substrate at a special active site in the enzymethe enzyme

Activation EnergyActivation Energy

Activation energy is Activation energy is the amount of the amount of energy required for energy required for the reaction to take the reaction to take placeplace

Enzymes reduce Enzymes reduce this by either this by either bringing substrates bringing substrates together or helping together or helping them to break apartthem to break apart

Lock and Key TheoryLock and Key Theory

All enzymes have an All enzymes have an active siteactive site

This is a special 3 This is a special 3 dimensional dimensional arrangement of arrangement of amino-acids which amino-acids which create a space in the create a space in the enzyme where enzyme where substrates can bondsubstrates can bond

Only a specific Only a specific enzyme can bind to enzyme can bind to this sitethis site

Active SitesActive Sites