ENZYMES What is an enzyme Enzymes are protein

ENZYMES

What is an enzyme? 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.

Naming an enzyme: Usually end in –ase Derived from the name of the substrate Ex. Maltase splits maltose into 2 glucose molecules Enzymes that break down: proteins = proteases lipids = lipases

What is a catalyst? Catalyst – a substance that brings about a reaction without being changed itself Is an enzyme a catalyst? YES

What is a substrate? Substrate – the substance that an enzyme acts upon

What is the active site? Active site – the region on the surface of an enzyme where the substrate molecules attach The active site is located on the enzyme

What is the enzyme-substrate complex? 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

Lock and Key Model

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

Induced-Fit Model

Factors that affect enzyme action 1. 2. 3. 4. 5. Small amounts of an enzyme can cause the reaction of large quantities of substrate. Enzymes work best at certain temperatures. Enzymes work best at a certain p. H. The rate of reaction depends on the concentrations of the enzyme and the substrate. Sometimes enzymes need a coenzyme to function.

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

What is a coenzyme? Coenzyme – allows an enzyme to perform its function Example of a coenzyme: a vitamin