Question

If we assume that the 'lock and key model' of the enzyme-substrate interaction is correct, which of these conditions is absolutely true?

• A. The enzyme can bind to substrates of only one shape
• B. Substrates can change the shape of the active site
• C. There is a competition between different substrates to bind to the active site
• D. There is a change in the shape of the active site after binding to the substrate

Answer 1

The correct option is A

The enzyme can bind to substrates of only one shape

The specific action of an enzyme with a single substrate can be explained using a Lock and Key analogy first postulated in 1894 by Emil Fischer. In this analogy, the lock is the enzyme and the key is the substrate. Only the correctly sized key (substrate) fits into the key hole (active site) of the lock (enzyme).