Vitamin C

Vitamin C is essential for the production of collagen, the primary protein comprising connective tissue. Vitamin C (also known as ascorbic acid) is involved in collagen synthesis at every level. The precursor to collagen, procollagen, is made up primarily of the amino acids glycine and proline, obtained through the diet. The formation of procollagen has been shown to increase eight-fold with prolonged exposure to vitamin C. In the conversion from procollagen to collagen, the proline must be hydroxylated (have a hydroxyl group added). Then, in order to become mature collagen, lysine, another amino acid, is converted into hydroxyl-lysine. These two hydroxylation reactions are catalyzed by two different enzymes: prolyl-hydroxylase, and lysyl-hydroxylase. Vitamin C is a cofactor in both of these enzymatic reactions. In a Korean study, vitamin C increased the expression of the enzyme prolyl-hydrolase, by 1700%. However when vitamin C is used in these biochemical reactions one molecule of vitamin C is destroyed for each single reaction. For this reason, vitamin C stores must be continuously replenished in order to sustain collagen synthesis.

References:

  1. Regulation of Collagen Synthesis by Ascorbic Acid Murad S, Grove D, Lindberg KA, Reynolds G, Sivaraja A, Pinnell SR Proc Natl Acad Sci USA. 1981 May;78(5):2879-82.
  2. "Ascorbate Is Consumed Stoichiometrically in the Uncoupled Reactions Catalyzed by Prolyl 4-Hydroxylase and Lysyl Hydroxylase" Myllyia R, Majamas K, Gunzler V, Hartmut M, Hanauske-Abel, and Kivirikko K The Journal of Biological Chemistry Vol. 259, no. 9 1984 May 10 pp.5403-5406.
  3. Lee, J. and Cho, Y. Effect of Ascorbic Acid, Silicon and Iron on Collagen Synthesis in the Human Dermal Fibrobroblast Cell, Medical Nutrition. http://www.fasebj.org/cgi/content/meeting_abstract/22/2_MeetingAbstracts/672