Question

Illustrate the lock and key hypothesis of enzyme action

Answer 1

Hint:Enzymes are biological catalysts that drive chemical reactions by reducing activation energy. Enzymes are proteins made up of one or more polypeptide chains.

Complete answer:
A substance that serves to generate a chemical reaction is a catalyst, and specific substances that catalyse biochemical reactions are called enzymes. When the substrates bind to the active site of the enzyme, the enzyme catalyses and a chemical reaction begins. The active site is the unique location of the enzyme that is coupled with the substrate. The attachment of the substrate to the enzyme induces changes in the distribution of electrons in the substrate's chemical bonds. This eventually results in reactions that contribute to the formation of products. Products are released from the enzyme surface to recycle the enzyme for a further reaction step. The active site has a unique geometric shape which is complementary to the geometric shape of a substrate fragment. This clearly tells that the enzymes can specifically react only with one or a very few similar compounds.

The basic activity of a single substrate enzyme can be explained using a Lock and Key analogy. In this example, the lock is the enzyme, and the substrate is the key. Only the right size key that’s the substrate goes into the keyhole which is the active site of the lock that’s the enzyme. Other keys that are smaller, larger or with incorrectly positioned teeth on keys do not fit into the lock. Just only the appropriately shaped key unlocks the lock.

Note:Emil Fischer first postulated lock and key hypothesis of the enzyme in 1894. The enzymes work in a very complex structure. Generally, one unit of enzyme will have only one active site which is capable of the binding substrate.