Enzymes

Enzymes

• Enzymes are protein molecules that act as a biological catalysts to speed up biological reactions.

• Enzymes remain unchanged by the reaction and can br used many times.

Activation Energy

Enzymes speed up reactions by lowering the activation energy needed for a reaction to take place.

One enzyme for one reaction

• The compound on which an enzyme acts is called the substrate.

• Enzymes are usually specific - they only work on one substrate.(Also known as substrate-specific)

Active site

• Enzymes have a specific region where the substrate binds and where catalysis occurs. This is called the active site.

• When a substrate binds to an enzyme’s active site, an enzyme-substrate complex (ESC) is formed.

Enzyme models( how enzymes work) - 1. lock and key model

Proposes that the enzyme and substrate EXACTLY match

Enzyme models( how enzymes work) - 2. Induced Fit Model

• The enzyme adjusts its shape slightly to fit the substrate

• This explains why some enzymes can bind to more than one type of substrate

This is a more precise version of the previous version