ENZYMES What are enzymes Enzymes are proteins that

ENZYMES

What are enzymes? Enzymes are proteins that act as biological catalysts. Their job is to speed up chemical reactions that take place in cells. How do they help speed up chemical reactions? They lower or reduce the activation energy of the chemical reaction.

Why are enzymes known as “catalysts”? A catalyst is a substance that speeds up the rate of a chemical reaction. Since enzymes speed up chemical reactions they are known as “catalysts”.

Chemical reactions need a certain amount of energy to get started, this energy is called the activation energy.

Why are enzymes important? ◦ All chemical reactions in living organisms require enzymes to work. enzyme Synthesis Enzymes ◦ Build molecules + ◦ Dehydration Synthesis Digestive Enzymes ◦ Break down molecules ◦ Hydrolysis We can’t live without enzymes! ◦ enzyme +

Steps of Enzyme Activity Substrate binds to enzyme Enzyme 1. 2. Enzyme 3. Enzyme is unchanged and free to be reused in another chemical reaction.

Remember: Enzymes can help build or break down molecules. Dehydration Synthesis (“building”) REACTION Hydrolysis (“break down”) REACTION

“Lock & Key” Model Shows Enzyme Specificity

“Denature” means to change the shape of an enzyme. When this happens the enzyme does not function or work properly. Temperature p. H Salinity

Factors that affect Enzyme Activity: 1. temperature 2. p. H level X = optimal temperature X 3. enzyme & substrate concentration X = optimal p. H X Enzyme concentration

4. Inhibitors – block the active site Normal

If enzyme k 3 is denatured, the level of which substance will increase?

If enzyme FDH is denatured, the level of which substance will increase?