Chymotrypsin and lysozyme are key enzymes with specific roles in digestion and defense, respectively. The correct answer is (B) Q, R.

Enzyme Functions

Chymotrypsin is a serine protease that performs hydrolytic cleavage of peptide bonds, particularly those next to aromatic amino acids like phenylalanine, tyrosine, and tryptophan. Lysozyme catalyzes the cleavage of glycosidic C–O bonds in bacterial cell wall peptidoglycans, specifically between N-acetylmuramic acid and N-acetylglucosamine.

Option Analysis

• P (Removal of successive carboxyl terminal residues): This describes exopeptidases like carboxypeptidases, not chymotrypsin, which is an endopeptidase acting internally on peptide bonds.​

• Q (Hydrolytic cleavage of peptide bond): Matches chymotrypsin exactly, as it hydrolyzes peptide amide bonds via its catalytic triad (Ser-195, His-57, Asp-102).​

• R (Cleavage of glycosidic C–O bond): Matches lysozyme, which hydrolyzes β-1,4 glycosidic bonds in peptidoglycans, lysing Gram-positive bacteria.

• S (Oxygen transport in blood): Relates to hemoglobin, unrelated to either enzyme.​

Why (B) Q, R? Pairs chymotrypsin’s peptide bond hydrolysis (Q) with lysozyme’s glycosidic bond cleavage (R). Other options mismatch: (A) wrongly assigns P to chymotrypsin; (C) pairs Q with irrelevant S; (D) ignores chymotrypsin entirely.

Introduction to Chymotrypsin and Lysozyme Functions

In biochemistry, chymotrypsin and lysozyme functions are pivotal for digestion and immunity. Chymotrypsin excels in peptide bond hydrolysis, breaking down proteins in the gut, while lysozyme targets glycosidic bond cleavage in bacterial walls. This GATE Life Sciences question highlights their roles for exam prep.

Chymotrypsin: Master of Peptide Bond Hydrolysis

Chymotrypsin, a pancreatic serine protease, cleaves peptide bonds after large hydrophobic residues like tyrosine or phenylalanine. Its mechanism involves a catalytic triad forming an acyl-enzyme intermediate, enabling efficient protein digestion. In competitive exams like GATE, it’s contrasted with exopeptidases to test endopeptidase specificity.​

Lysozyme: Expert in Glycosidic Bond Cleavage

Lysozyme hydrolyzes β-1,4 glycosidic C–O bonds between N-acetylmuramic acid (NAM) and N-acetylglucosamine (NAG) in peptidoglycans. Found in tears and saliva, it defends against Gram-positive bacteria by rupturing cell walls. This antibacterial action underscores its innate immune role.

GATE Q36 Breakdown: Matching Enzymes to Actions

• P mismatches both (carboxypeptidase trait).

• Q fits chymotrypsin perfectly.

• R aligns with lysozyme.

• S is hemoglobin’s job.
  Answer (B) Q, R is precise for chymotrypsin and lysozyme functions.

Exam Relevance for Life Sciences Students

For GATE aspirants in Jaipur or beyond, mastering chymotrypsin and lysozyme functions clarifies enzyme classification: proteases vs. glycosidases. Practice PYQs to differentiate hydrolytic actions.​