<prompt> Vitamin C is necessary in the formation of collagen. It is required for the conversion of:Proline to hydroxyprolineBeta-carotene to vitamin AGlutamate to gamma-carboxyglutamatePyridoxine to pyridoxal phosphate  <response>: Ans. a Proline to hydroxyprolineRef: Harpers Biochemistry, 30th ed. pg. 47, 562 Ascorbic acid is needed for a variety of biosynthetic pathways, by accelerating hydroxylation and amidation reactions. In the synthesis of collagen, ascorbic acid is required as a cofactor for following enzymes: Prolyl hydroxylase Lysyl hydroxylase These two enzymes are responsible for the hydroxylation of the proline and lysine amino acids in collagen. Remember, Hydroxyproline and hydroxylysine are important for stabilizing collagen by cross-linking the propeptides in collagen. Clinical effects if there is defective collagen fibrillogenesis: Impaired wound healing. Impaired bone bormation Abnormal bleeding due to fragile capillaries. 