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. Both Assertion and Reason are incorrect

Answer 1

Hint: We know that enzymes are the substances that speed up the reaction. All enzymes are proteins (globular). They are specific for a particular reaction and for a particular substance. The naming of the enzymes is done considering the class of compounds on which they work.

Complete step by step answer:
Let’s understand the exopeptidase in detail. It is one type of peptidase that cleaves the single amino acid at the terminals of the proteins. Some examples of exopeptidase are aminopeptidases, carboxypeptidase etc. It is also known as dipeptides.

Now, come to the question. Carboxypeptidase enzyme is the enzyme which is synthesized in pancreas and secreted into the small intestine is called carboxypeptidase. The enzyme hydrolyses the amide bond (peptide bond) at the C terminal end of proteins. Carboxypeptidase cleaves the single amino acid at the terminals of the proteins, so it is an exopeptidase. But, it cleaves the C terminal of protein. So, Assertion is correct but Reason is incorrect.

So, the correct answer is Option C.

Additional Information:

We know that enzymes are very particular for some reactions. And the naming of enzymes is done considering the class of compounds on which they work. For example, maltase is an enzyme that catalyses hydrolysis of maltose into glucose.
C_{12}H_{22}O_{11}\overset{Maltase}{\rightarrow}2C_{6}H_{12}O_{6}
Maltose Glucose
Enzymes are also named after the reaction, where they are used. For example an enzyme that catalyses the oxidation of one substance with simultaneous reduction of another substance is known by the name oxidoreductase. The Name of all enzymes ends with ‘ase’.

Note: A kind of protein that cleaves the peptide bond within the protein molecule is termed as endopeptidase. This protein is also known as enterokinase or enteropeptidase. Some examples of this type of proteins are pepsin, trypsin, chymotrypsin etc.