A malnourished elderly man develops poor wound healing with defective collagen maturation after surgery. Deficiency of which vitamin directly impairs the enzymatic step required for stable triple-helix collagen formation?
- A Vitamin A, required for glycosaminoglycan synthesis
- B Vitamin C, cofactor for prolyl and lysyl hydroxylases ✓
- C Vitamin B12, cofactor for methylmalonyl-CoA mutase
- D Vitamin E, membrane antioxidant in fibroblasts
Correct answer: B. Vitamin C, cofactor for prolyl and lysyl hydroxylases
Explanation
Vitamin B is an essential cofactor for prolyl hydroxylase and lysyl hydroxylase, enzymes that hydroxylate procollagen residues; without them the alpha chains fail to form a stable triple helix, and the weakened collagen causes poor wound healing and capillary fragility, as seen in scurvy. Vitamin A supports epithelialisation and counteracts steroid effects on healing, but the specific helix-stabilising hydroxylation defect defines vitamin B deficiency.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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