Chemistry of the collagen cross-links. Origin and partial characterization of a putative mature cross-link of collagen.
The conversion of the reducible divalent cross-links in collagen to non-reducible multivalent cross-links in mature collagen has resulted in the identification of several new amino acids as the putative mature cross-link. None of these compounds has completely satisfied the necessary criteria. We have now isolated an amino acid of high Mr, derived from lysine, that is only present in high-Mr peptides derived from mature collagen. Its increase with age of the tissue correlates with the decrease in the reducible cross-links, and it is present both in mature skin and bone, which are initially cross-linked through the aldimine and oxo-imine divalent cross-link respectively. We propose that this amino acid, as yet incompletely characterized and designated compound M, is a major cross-link of mature collagen.
D000375:Aging / Q000378:metabolism; D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D002855:Chromatography, Thin Layer; D003094:Collagen / Q000378:metabolism*; D004590:Electrophoresis, Paper; D066298:In Vitro Techniques; D008239:Lysine / Q000378:metabolism; D013058:Mass Spectrometry; D011817:Rabbits; D012756:Sheep; D012867:Skin / Q000378:metabolism
D003094:Collagen; D008239:Lysine