Scurvy impairs wound healing because vitamin C is the required cofactor for an enzyme that modifies collagen after translation. Which reaction is defective?

• A Glycosylation of hydroxylysine residues in the Golgi apparatus
• B Hydroxylation of proline and lysine residues in the rough endoplasmic reticulum ✓
• C Cleavage of N-terminal propeptides by peptidases outside the cell
• D Oxidative deamination of lysine residues to form allysine cross-links

Explanation

Prolyl-4-hydroxylase and lysyl hydroxylase require vitamin C to keep iron in the ferrous state; without it, procollagen alpha chains cannot form stable triple helices and are degraded inside the fibroblast. Glycosylation (option A) needs hydroxylysine but does not require vitamin C directly, and propeptide cleavage occurs extracellularly after secretion.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.