Topics:
Animal Nutrition, Animal Refresher
Enzyme Missing for Vitamin C Synthesis
Vitamin C is not synthesized in the body of a human, guinea pig, cat and poultry due to the absence of an enzyme:
- Xanthine oxidase
- L-gulonolactone oxidase — Correct Answer
- Cytochrome oxidase
- Carbonic anhydrase
Explanation:
Correct Answer: L-gulonolactone oxidase
Most mammals can synthesize Vitamin C (L-Ascorbic acid) from hexose sugar (glucose). However, certain species including humans, other primates, and guinea pigs lack the terminal biosynthetic enzyme L-gulonolactone oxidase, making Vitamin C an essential dietary nutrient for them.
Vitamin C — Key Facts from Notes
| Item | Detail |
|---|---|
| Chemical name | L-Ascorbic acid |
| Deficiency disease | Scurvy / Bleeding gums; 'Pithed frog' condition in babies |
| Precursor | Hexose sugar (glucose) |
| Solubility | Water-soluble (along with all B-complex vitamins) |
Metalloenzymes — from Notes
| Metal | Enzyme |
|---|---|
| Copper | Cytochrome oxidase, Uricase, Ceruloplasmin |
| Selenium | Glutathione peroxidase |
| Zinc | Carbonic anhydrase, Alcohol dehydrogenase, Alkaline phosphatase |
📚 About this Topic — Animal Nutrition
This multiple choice question is from Animal Nutrition, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Nutrition to strengthen your preparation.
