Question

Assertion:Carboxypeptidase is an exopeptidase.
Reason:It cleaves the N-terminal bond.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Assertion is incorrect but Reason is correct

Answer 1

Hint:We know that carboxypeptidase is an enzyme which synthesized in the pancreas and secreted into the small intestine. Here we are asked whether there is an exopeptidase which we can find out by whether the peptide chain is broken or not.


Complete step by step answer:
So, we understood what carboxypeptidase is from the hint. As we said it is an enzyme.
-Here, we have to check whether the assertion and reason are correct or not and also whether the reason is the correct explanation for the assertion given.
The assertion given here is Carboxypeptidase is an exopeptidase, we have to check whether it is correct or not.
-We know that the carboxypeptidase is a pancreatic exopeptidase, which hydrolysis and the peptide bond will reduce the C-terminal. Therefore, we understood that it breaks the peptide chain at the terminal ends. It leaves the carboxy terminal amino acids that have aromatic or branched aliphatic side chains. Hence, we get our Assertion as correct since it is an exopeptidase.
-Now coming to our reason, let us check whether that is correct or nor also whether it gives a correct explanation for our Assertion. We clearly said in our assertion that peptide bonds will reduce the C-terminal not N-terminal bonds. Hence, we can say that Reason is incorrect.
-The correct option for the Assertion Reason question, Assertion is correct but Reason is incorrect.
i.e., option (c) is correct.

Note:The cleavage of N-terminal bonds is often seen on aminopeptidase. We should not confuse carboxypeptidase. The carboxypeptidase has mainly functioned during the digestion of food which was the first carboxypeptidase studied. However, nowadays it is known for its involvement in catabolism.