Biochemistry Absence of which of the following enzyme in humans is responsible for the inability to synthesize ascorbic acid? A L-Glucuronic acid oxidase B L-Gulonic acid reductase C L-Gulonolactone oxidase D L-Gulonolactone reductase 💡 Explanation Absence of which of the following enzyme in humans is responsible for the inability to synthesize ascorbic acid? ✓ Correct Answer: C. L-Gulonolactone oxidase