A patient receiving total parenteral nutrition without trace element supplementation develops a dermatitis around the eyes, nose, and mouth, along with impaired wound healing and dysgeusia. Serum alkaline phosphatase and lactate dehydrogenase activities are decreased. The deficient micronutrient is a cofactor for which category of enzymes?
- A Selenium-dependent glutathione peroxidases
- B Copper-dependent ceruloplasmin and lysyl oxidase
- C Zinc-dependent metalloenzymes including carbonic anhydrase, carboxypeptidase, and alcohol dehydrogenase ✓
- D Manganese-dependent mitochondrial superoxide dismutase (Mn-SOD)
Explanation
The clinical picture — periorificial dermatitis, acral rash, alopecia, impaired wound healing, and dysgeusia — is classic zinc deficiency. Zinc is an essential cofactor for over 300 enzymes, including alkaline phosphatase (decreased activity is a sensitive marker of zinc deficiency), carbonic anhydrase, carboxypeptidases A and B, alcohol dehydrogenase, and multiple metalloproteinases involved in wound healing. Zinc also stabilizes DNA-binding zinc-finger motifs in transcription factors, explaining its role in immune function and cell division. Serum alkaline phosphatase activity is routinely used to monitor zinc status.
Reference: Harper's Illustrated Biochemistry, 32nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.