explain the lock and key hypothesis of enzyafic action
Answers
Answer:
Enzymes catalyze the rate of reaction. They increases the rate of reaction by binding to substrate. It binds to specific substrate to yield the desired product. Enzyme when binds to substrate, it forms an intermediate complex before the final product is formed. This is two way reaction. It can be represented as follows:
1st step : Enzyme (E) + Substrate (S) = Enzyme Substrate Complex (ES)
2nd step: Enzyme Substrate Complex (ES) = Enzyme (E) + Product (P).
In order to explain the mode of action of enzyme, Fischer proposed a Lock and Key hypothesis. According to this theory, if the right key fits in the right lock, the lock can be opened, otherwise not. Similarly, if the right enzyme fits in the right substrate, the product is formed, otherwise not. Shape of enzymes provides surface configurations into which other molecules can fit. The molecules which are acted upon by the enzymes are called substrates of the enzymes. Substrates with the proper geometric shape can fit into the active site of the enzymes. The active site of enzyme is highly specific for its substrate. The enzyme and substrate fit like a lock and key and thus is a lock and key model of enzyme action. However, sometimes other molecules which are similar to the substrate can also combine with the active site of an enzyme. In this case, the molecule completes with the substrate and the reaction may either slow down or stop. Such substance is called as the competitive inhibitor as they act to prevent the production of a substance.
Answer:
The specific action of an enzyme with a single substrate can be explained using a lock and key analogy postulated in 1894 by Emil Fischer. In this analogy, the lock is enzyme and the key is substrate. Only the correctly sized key ( substrate) fits into the key hole ( active site) of the lock ( enzyme )