BIOMOLECULES AND ENZYMES

Detailed explanation-1: -The lock-and-key theory of enzyme action proposes that the enzyme’s active site and the shape of the substrate molecule are complementary to one another. This allows the substrate to fit into the enzyme, like how a key would fit into a lock. If the substrate doesn’t fit, then the enzyme will not act on it.

Detailed explanation-2: -A Lock and Key analogy may be used to describe the fundamental action of a single substrate enzyme. In this case, the enzyme is the lock, and the substrate is the key. Only the correct size key, which is the substrate, enters the keyhole, which is the active site of the lock, which is the enzyme.

Detailed explanation-3: -The Lock and Key model explains that the enzyme needs to bind substrate, but once the reaction progresses to the transition state and product formation, the active site would not be able to accommodate this change.

Detailed explanation-4: -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).