Define Interaction of vitamin c with Ascorbic acid and Leucine?

Ascorbic acid: The biologically active form, ascorbate, is a cofactor or co-  substrate for eight isolated enzymes involved in hydroxylation of amino  acids, metabolism of tyrosine etc. It protects lipids, protein and membrane structures from oxidative damage. It also regulates protein translation and gene transcription. Since ascorbic acid closely resembles glucose, most mammals can synthesize ascorbate from glucose. However, man lacks the terminal enzyme in the biosynthetic pathway and hence must ingest ascorbic acid to survive.

Leucine: Excess of the amino acid, leucine in the diet antagonizes the function of vitamin B₆, and impairs the conversion of tryptophan to niacin.