B4

Enzyme

A protein that functions as a biological catalyst, made in all living cells, and can be used repeatedly without being used up during a reaction.

Enzyme Action

The ability of enzymes to join two molecules together to form a more complex substance, with the enzyme and substrate requiring complementary shapes for the reaction to occur efficiently.

Catalase

An enzyme found in most cells that can break down 40,000 hydrogen peroxide molecules per second.

Temperature and Enzymes

Most chemical reactions, including enzyme-controlled reactions, increase in rate as temperature increases, but enzymes stop working and denature at temperatures above 50 degrees Celsius.

Test for Enzymes

Heating a substance to its boiling point and observing if the reaction still occurs can determine if an enzyme is present.

Enzymes and pH

Enzymes have specific pH ranges at which they work best, with acid and alkaline conditions affecting the chemical properties of the enzyme. Extreme pH levels can denature enzymes irreversibly.