Enzyme catalysis

What are enzymes?

Proteins that speed up chemical reactions in the body.

Why are enzymes important?

They help the body's metabolism happen fast enough.

How do enzymes act as catalysts?

Substrates fit into active sites to become products, and enzymes are reused.

How do enzymes speed up reactions?

By lowering the energy needed to start them.

Catalase function

Breaks down hydrogen peroxide into water and oxygen.

Enzymes in diagnosis and medicine

Blood tests of enzyme levels monitor tissue damage or disease.

Statins and enzymes

Statins inhibit HMG-CoA reductase to help the body make cholesterol.

Effect of temperature and pH on enzymes

Extremes can change enzyme shape and stop them working.

Effect of substrate amount on reactions

More substrate increases speed until Vmax is reached.

Reversible vs. irreversible inhibition

Reversible inhibitors detach for reuse; irreversible permanently inactivate the enzyme.

What are cofactors?

Inorganic ions like Mg²⁺, Zn²⁺, or Fe³⁺ needed by enzymes.

What are coenzymes?

Organic helpers often made from vitamins, such as NAD.

Apoenzyme vs. holoenzyme

An apoenzyme lacks its helper; an active holoenzyme has it.