Set 7 — Factors Affecting Enzyme Activity & Denaturation

What are the two main factors affecting enzyme activity?

Temperature and pH

What is optimum enzyme activity?

When an enzyme works at its maximum rate under ideal conditions

What is optimum temperature?

The temperature at which an enzyme works at its maximum rate

What is optimum pH?

The pH at which an enzyme works at its maximum rate

What is denaturation?

The loss of an enzyme's specific three-dimensional shape and function

What are two causes of enzyme denaturation?

Extreme temperatures and extreme pH

What happens to an enzyme during denaturation?

Its active site changes shape and the enzyme loses its function

Why does denaturation stop enzyme activity?

The substrate can no longer bind properly to the altered active site

What happens to enzymes at low temperatures?

Their activity slows down

Do low temperatures normally denature enzymes?

No they usually only slow enzyme activity

Why does enzyme activity increase as temperature rises towards the optimum?

Molecules gain kinetic energy causing more frequent successful collisions

What happens to enzyme activity above the optimum temperature?

The rate decreases as the enzyme begins to denature

What happens when pH moves far from the optimum?

The active site may change shape and enzyme activity decreases

Is enzyme denaturation usually reversible?

No denaturation is usually irreversible

Why do enzymes have different optimum conditions?

Different enzymes have different structures and active sites