97. Given below are two statements:
Statement I: Serine is part of a catalytic triad in proteases that also includes histidineand
aspartic acid.
Statement II: Catalytic triads are responsible for peptide hydrolysis.
In light of the above statements, choose the most appropriate answer from the options
given below
(a) Both statement I and statement II are correct,
(b) Both statement I and statement II are incorrect,
(c) Statement I is correct and statement II is incorrect,
(d) Statement II is correct and statement I is incorrect

Detailed Explanation:

Proteases are enzymes that catalyze the hydrolysis of peptide bonds in proteins, and many of them employ a catalytic triad—a highly conserved structural motif that facilitates this reaction with remarkable efficiency.

Statement I: Serine is part of a catalytic triad in proteases that also includes histidine and aspartic acid.

This is true. In serine proteases, such as trypsin and chymotrypsin, the active site contains a catalytic triad made up of:

• Serine, which acts as the nucleophile,

• Histidine, which acts as a base to deprotonate the serine,

• Aspartic acid, which stabilizes the positively charged histidine during catalysis.

These three residues work in concert to perform nucleophilic attack on the peptide bond of the substrate.

Statement II: Catalytic triads are responsible for peptide hydrolysis.

This is also true. The catalytic triad facilitates the cleavage of peptide bonds by enhancing the nucleophilic power of the serine residue. This is central to the function of serine proteases, which break down proteins during digestion, immune responses, and cellular regulation.

Conclusion:

Both statements are scientifically accurate. The catalytic triad is a crucial feature of many proteases, making (a) the correct answer.