Aim: What are enzymes?

I. Enzymes (Organic Catalysts) – proteins that change the rate of a chemical reaction (usually speeds it up).

A. Characteristics of Enzymes

1. Enzymes are specific – they have specific shapes and only work on particular substrates.

a. Substrate – the substance an enzyme acts upon. Ex: The enzyme maltase only works on the substrate maltose.

2. Enzymes are named after the substrate they act upon. Ex: Lactase works on lactose, lipase works on lipids, and etc.

ASE ending

3. Enzyme Substrate Complex – when enzyme and substrate are fitted together to perform a reaction.

a.The substrate changes in a specific way.

b.The enzyme does not change and can be used over and over to work on the same substrate.

4. Lock and Key Model – The fit of the substrate in the active site resembles the fit of a key in a lock.

Why can’t Lipase work on Maltose?

Which enzyme would work on the substrate sucrose?

What is the Lock and Key Model?