Collagen, Vitamin C, Scurvy, Lysine and proline

http://www.livestrong.com/article/428024-amino-acids-to-produce-collagen/

AMINO ACID MODIFICATION

Glycine accounts for one-third of the amino acids in the collagen molecule. Lysine and proline, which constitute another one-sixth of the collagen strand's amino acid content, are converted to hydroxylysine and hydroxyproline before they are incorporated into the strand. The enzyme that performs these conversions requires vitamin C as a cofactor. Hence, a deficiency of vitamin C inhibits the conversion of proline and lysine and interferes with the production of collagen. This interference is the basis for scurvy, a nutritional disease that leads to the breakdown of your skin and mucous membranes.