Absence of which of the following enzyme in humans is responsible for the inability to synthesize ascorbic acid?
L-Glucuronic acid oxidase
L-Gulonic acid reductase
L-Gulonolactone oxidase
L-Gulonolactone reductase
Uronic acid pathway is an alternate pathway for oxidation of glucose without ATP formation. Fig: Uronic acid pathway An intermediate (L-gluconate) of this pathway can be used for the synthesis of ascorbic acid in plants by enzyme L-gulonolactone oxidase. However, In human beings and other primates, as well as guinea pigs, bats, and some birds and fishes, ascorbic acid cannot be synthesized because of the absence of L-Gulonolactone oxidase.
Vitamins and Minerals