Enzymes 1 What Are Enzymes Enzymes are Proteins

What Are Enzymes? • Enzymes are Proteins that act as a Catalyst to accelerate

Enzymes • Each enzyme is made to work with only one chemical called its

How do enzymes Work? Every reaction requires a “starting energy” Enzymes work by weakening

Enzymes Without Enzyme With Enzyme Free Energy Free energy of activation Reactants Products Progress

Enzyme-Substrate Complex The substrate bonds to the enzyme at a special area called the

Active Site The substrate bonds to the enzyme at a special area called the

Enzyme Activity • Once the substrate bonds, the enzyme changes shape to start the

Enzyme Activity • The substrate is chemically changed by the enzyme and then released.

What Affects Enzyme Activity? • Every enzyme has its own specific temperature and p.

1. Environmental Conditions 1. Extreme temperatures can damage or denature enzymes 2. Strong changes

2. Cofactors and Coenzymes • Some enzymes work with partners or helpers • Inorganic

Enzyme Inhibitors - Inhibitors are chemicals that slow down or block an enzyme from

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Enzymes 1

What Are Enzymes? • Enzymes are Proteins that act as a Catalyst to accelerate (help start) a chemical reaction. 2

Enzymes • Each enzyme is made to work with only one chemical called its substrate. • A substrate and its enzyme fit together like a lock and key • After the reaction, only the substrate is chemically changed. The enzyme can be reused. • Enzyme names usually end in –ase. Example: Lactase 3

How do enzymes Work? Every reaction requires a “starting energy” Enzymes work by weakening bonds and lowering that activation energy, so the reaction can happen faster/easier 4

Enzymes Without Enzyme With Enzyme Free Energy Free energy of activation Reactants Products Progress of the reaction 5

Enzyme-Substrate Complex The substrate bonds to the enzyme at a special area called the “active site” Substrate Joins Enzyme 6

Active Site The substrate bonds to the enzyme at a special area called the “active site” Active Site Substrate Enzyme 7

Enzyme Activity • Once the substrate bonds, the enzyme changes shape to start the reaction 8

Enzyme Activity • The substrate is chemically changed by the enzyme and then released. After which, the enzyme returns to normal. The enzyme can now move on to a new substrate Active Site Enzyme induced fit 9

What Affects Enzyme Activity? • Every enzyme has its own specific temperature and p. H that is optimal (best). Changes in these optimal conditions can slow down or denature (destroy) enzymes • Three factors that affect enzyme activity: 1. Environmental Conditions 2. Cofactors and Coenzymes 3. Enzyme Inhibitors 10

1. Environmental Conditions 1. Extreme temperatures can damage or denature enzymes 2. Strong changes in p. H (in either direction) can also denature enzymes 3. Too many ions (salts) can also denature enzymes. 11

2. Cofactors and Coenzymes • Some enzymes work with partners or helpers • Inorganic substances (zinc, iron) and vitamins are sometimes needed for proper enzymatic activity • Example: Iron must be present in the protein hemoglobin in order for it to pick up oxygen. Without Iron, it doesn’t work. 12

Enzyme Inhibitors - Inhibitors are chemicals that slow down or block an enzyme from working. This helps your body turn enzymes on and off when you need to. Substrate inhibitor Enzyme 13