Name the class of enzyme that usually catalyze the following reaction: S−G + S# → S + S#−G Where, G → a group other than hydrogen; S → a substrate; S# → another substrate

Solution & Explanation

Answer: (A) Transferase. Solution: The reaction S−G + S# → S + S#−G shows a group G (other than hydrogen) being transferred from one substrate to another. By NCERT's classification of the six enzyme classes, this group-transfer reaction between a pair of substrates is the defining activity of transferases. Ligases join compounds, hydrolases cleave bonds by adding water, and lyases remove groups leaving double bonds, so none of these fit. NCERT Reference: Ch 9, p.117, line ~26 — "Transferases: Enzymes catalysing a transfer of a group, G (other than hydrogen) between a pair of substrate S and S’ e.g., S - G + S’ → S + S’ - G"