Lyases: Non-Hydrolysis Group Removal — NEET Biology
✅ Asked in NEET 2026The reaction X-C-C-Y -> X-Y + C=C is catalysed by which enzyme class?
The reaction X-C-C-Y -> X-Y + C=C is catalysed by which enzyme class?
Enzymes that catalyse the removal of groups from substrates by mechanisms other than hydrolysis are
Answer & NCERT explanation
Correct answer: C — Lyases
Lyases catalyse removal of groups from substrates by mechanisms other than hydrolysis, leaving behind double bonds (or new ring structures), as shown in the reaction.
Read more NCERT concept on the PYQ
Lyases: Enzymes that catalyse removal of groups from substrates by mechanisms other than hydrolysis leaving double bonds.
Lyases are enzymes that remove groups from substrates WITHOUT breaking bonds through hydrolysis, instead creating double bonds (C=C, C=O, C=N). NTA tests this by distinguishing lyases from hydrolases—students often confuse them because both remove groups, but hydrolases use water while lyases don't. The key trap is thinking all group-removing enzymes are hydrolases; remember that lyases specifically use elimination mechanisms. To get it right, focus on the mechanism difference: hydrolysis breaks bonds using H₂O, while lyases remove groups and form unsaturation (double bonds). Examples like decarboxylase (removes CO₂) and aldolase (cleaves C-C bonds) help cement this distinction.
What does NCERT say about Lyases Enzymes that catalyse?
Has this concept appeared in NEET?
Which chapter is this from?
Through deep analysis of NEET and NTA, 88 of 90 questions from the NEET 2026 paper were matched straight from the MedicNEET Biology question bank.
88/90MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.