Enzymes – are protein substances that are necessary for most of the chemical reactions that occur in living cells

Enzymes affect the rate or speed of a reaction.

Usually end in –ase Derived from the name of the substrate

Ex. Maltase splits maltose into 2 glucose molecules

Enzymes that break down:proteins = proteaseslipids = lipases

Catalyst – a substance that brings about a reaction without being changed itself

Is an enzyme a catalyst?

YES

Substrate – the substance that an enzyme acts upon

Active site – the region on the surface of an enzyme where the substrate molecules attach

The active site is located on the enzyme

Enzyme-substrate complex – when the substrate molecule comes in contact with the active site of an enzyme

The enzyme-substrate complex is temporary.

The Lock and Key Model – is a theory that explains how the enzyme and substrate fit together

Each substrate can only fit into specific enzymes

Induced-Fit Model – the theory in which the enzyme slightly changes shape to allow the substrate to fit the active site of the enzyme

1. Small amounts of an enzyme can cause the reaction of large quantities of substrate.

2. Enzymes work best at certain temperatures.

3. Enzymes work best at a certain pH.4. The rate of reaction depends on the

concentrations of the enzyme and the substrate.

5. Sometimes enzymes need a coenzyme to function.

Denaturation – is when high temperatures cause the shape of the enzyme to change, so the active site no longer fits the substrate

Coenzyme – allows an enzyme to perform its function

Example of a coenzyme: a vitamin