NZYMESNZYMES

Amylase catalyses the breakdown of starch

Amylase Starch Amylase Maltose

Enzyme Substrate Enzyme Product

The Lock and Key Mechanism of Enzyme Action

In this diagram the enzyme breaks a large molecule into smaller ones. The same enzyme will also catalyse the reverse reaction – it will

join the smaller molecules together again.

The Induced Fit Hypothesis of Enzyme Action

When the substrate binds to the enzyme’s active site, it ‘induces’ a change of shape so that the substrate and enzyme become

fully complementary.

A Graph To Show That The Activation Energy Of A Reaction Is Smaller In The Presence Of An Enzyme.

DENATURATION

Enzymes are Proteins and will show a positive result with the Biuret test!

Don’t Forget!!!

Cofactors

The Effect of Temperature on the Rate of an Enzyme-Controlled Reaction

The Effect Of pH

The Effect Of pH on the Rate of an Enzyme-Controlled Reaction

The Effect Of Changing Substrate Concentration

The effect of changing the amount of substrate on the rate of an enzyme-controlled reaction. As the amount of substrate increases from

0 to B, the rate of reaction increases. As the amount of substrate increases from B to C, the rate of reaction does not increase any further.

Competitive Inhibitors

Non-Competitive Inhibitors

(ALLOSTERIC SITE)

The Effect of a Non-Competitive Inhibitor

The effect of a non-competitive inhibitor on the rate of an enzyme-controlled reaction. The rate of reaction is always lower with a non-

competitive inhibitor, however much substrate is present.

End-Point Inhibition

By acting as an inhibitor, the end-product of a series of reactions prevents its own production.

End-Point Inhibition continued…