NUTR 3210 Lecture Notes - Lecture 19: Nicotinamide Adenine Dinucleotide Phosphate, Glutathione Reductase, Procollagen-Proline Dioxygenase
23 Mar 2017
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In foods, mostly ascorbic acid, but small amounts of oxidized form (dehydroascorbic acid) exists: vit c tissue concentrations greater than plasma. Involved in a number of biological processes: collagen synthesis, tyrosine synthesis, neurotransmitter synthesis, vit c acts primarily as a reducing agent in these processes (cid:862)(cid:1006) ele(cid:272)t(cid:396)o(cid:374) do(cid:374)o(cid:396)(cid:863) Post-translation modification happens in the cell, and the product is exported from the cell into the extracellular matrix to join the collagen unit together. Vit c donates electrons to the iron component of prolyl hydroxylase to activate the enzyme and to encourage post-translation modification. Vitamin c reactivates the enzymes with electron donation. Vitamin c has two electrons to donate, so the hypothesis is that either there are two irons on the enzyme to donate to, or each vitamin c can activate two enzymes. Vitamin c oxidant defense: we just learned about the reactions of lipid peroxidation, and free radicals stealing electrons from pufa in cell membranes.
