Cambridge O Level Biology · Syllabus 5090 · Enzymes
Optimum temperature
What is Optimum temperature?
The temperature at which an enzyme has its greatest activity. Below it the rate is lower because molecules have less kinetic energy and collide less often; above it the rate falls rapidly because the enzyme becomes denatured. The optimum differs from enzyme to enzyme, and the enzyme still works, more slowly, at temperatures either side of it.
This definition is part of the Enzymes chapter in Cambridge O Level Biology.
Questions students ask about Optimum temperature
Do all enzymes have the same optimum temperature and pH?
No. Optima differ between enzymes. A stomach protease has an optimum of about pH 2, while a small-intestine protease has an optimum of about pH 8; if every enzyme shared one optimum, digestion in an acid stomach and an alkaline small intestine could not both work. An enzyme also works over a range of temperatures and pH values either side of its optimum, with its greatest activity at the optimum, not only at it.