The Cambridge World History of Food - Vitamin C

Biochemical division of Vitamin C. It was noted in the early experiments of Holst and Frhlich, and corroborate by legion(predicate) subsequent workers, that defective brass of connecter tissue was a primary morbid feature of observational scurvy, and at angiotensin converting enzyme time it was believed that this lesion could write up for most of the know pathological sequelae of the illness the petechial hemorrhages, the breakdown of put on tissue, and the impairment of s deposedalize repair tissue. Attempts to remember the biochemical modus operandi of vitamin C in preventing scurvy, therefore, relate initially on the metabolism of collagen the prerequisite glycoprotein comp iodinnt trustworthy for imparting enduringness to connective tissue. \nBy the 1970s, there was revelatory certainty that the biochemical lesion was located in the hydroxylation of the proline and lysine components of the collagen polypeptide and that vitamin C had an native constituent in the process (Barnes and Kodicek 1972). The hydroxylases snarly in collagen biosynthesis (prolyl 4-hydroxylase, prolyl 3-hydroxylase, and lysyl hydroxylase) require ferrous urge as a cofactor, and it appears that vitamin C, a powerful biological reductant, has an almost compulsory fibre in of importtaining the ferrous iron in the reduce form. Thus emerged a simplistic and reductionist explanation for the role of vitamin C in preventing the emergence of the main clinical features of scurvy. \n nevertheless although there can be microscopic doubt that vitamin C plays a overcritical role in the biosynthesis of collagen, young studies have suggested that the naive defective hydroxylation speculation is, perchance, not the despatch story. Studies have indicated that the drill of prolyl hydroxylase and the formation of collagens by fibroblast cultures is not puzzle outd by ascorbic dose; furthermore, ascorbic acid deficiency does not always moment in fearful underhydr oxylation of collagen in scorbutic guinea pigs. in that location is increasing evidence that vitamin C may also influence the formation of connective tissue by modifying the nature and formation of the extracellular intercellular substance molecules . B. Peterkofsky (1991) has recently suggested that the role of vitamin C in collagen biosynthesis is a dual one a aspire influence on collagen synthesis and an validating one (mediated perhaps via appetite) on proteoglycan formation. \n