1.4 Enzymes

Enzymes

Enzymes increase the rate of a specific chemical reaction – catalyse it

Have an active sit formed by the folding and binding of the polypeptide chain

Enzyme specificity: one enzyme binds to one substrate

Enzyme substrate binding

During enzyme catalysed reactions, reactants (substrates) are converted into products

Enzymes are not used up in the reactions they catalyse

Substrate binds to the active site

Bonds in the substrate are put under stress which lowers the amount of energy needed for the reaction to proceed

Substrate binds to the enzyme by weak bonds which often cause changes to the shape of the enzyme and the substrate

Induced fit model

Induced fit model escribes enzymes and substrates as biding together by lowering activation energy

Factors affecting enzyme activity

Temperature

pH

substrate concentration

enzyme concentration

presence of inhibitors

competitive inhibitors

compete with the substrate by binding to the active site of the enzyme

non-competitive inhibitors

bind to the enzyme away from the active site causing the shape of the enzyme to change