- Ascorbic acid serves as a common reductant/cofactor in many enzymatic reactions (especially those requiring reduced Fe2+).
1) Carnitine Synthesis
2) Catecholamine Synthesis
3) Peptide Hormone Synthesis
4) Tyrosine Metabolism
5) Generic Antioxidant
6) Role in Immune Function?
- The critical functional role is to serve as a cofactor for protocollagen hydroxylase, the enzyme responsible for hydroxylation of the prolyl and lysyl residues in collagen.
- The triple-helix structure of mature collagen is markedly stabilized by hydroxylation (Tm of 24 ºC vs. 58 ºC) as it allows the formation of a water-mediated hydrogen bond between collagen strands.
- By an independent mechanism, the synthesis of proteoglycans and protocollagen is decreased in ascorbic acid deficiency (inhibition of insulin-like growth factor I?).