Heidemann E, Linnert N
Hoppe Seylers Z Physiol Chem. 1984 Jul;365(7):781-9. doi: 10.1515/bchm2.1984.365.2.781.
It is shown that regions of unreduced, insoluble cow hide collagen, represented by the peptides alpha 1(I)-CB6, alpha 2(I)-CB4 and the alpha 2(I)-CB3,5, are involved in the formation of unreducible acid-stable and mature-type crosslinks. The characteristic ratio of the CNBr peptides in soluble type I collagen was found to be changed in the insoluble collagen of cow hides. The intensity of the bands of alpha 1(I)-CB6, alpha 2(I)-CB4 and alpha 2(I)-CB3,5, shown by dodecyl sulfate polyacrylamide gel electrophoresis, is significantly reduced in such samples, which indicates an involvement of these peptides in crosslink formation. The purified highly polymeric CNBr peptide fraction was also investigated to confirm the participation of the alpha 2 chain of type I collagen in mature crosslink formation. Chymotryptic digests of such material contain peptides which originate from alpha 2(I)-CB4, alpha 2(I)-CB3,5, and alpha 1(I)-CB6. Finally, acid hydrolysates of crosslinked material were screened carefully for crosslinks down to concentrations of 1 in 1000 amino acids. Only two compounds were detected, one identified as "hydroxyaldol-histidine" and the other an as yet unknown compound. These results indicate that both the alpha 1(I) and the alpha 2(I) chains are involved in mature crosslink formation and that the polymeric CNBr peptide fraction contains components crosslinked by so far uncharacterized, nonreducible crosslinks.
结果表明，由肽α1(I)-CB6、α2(I)-CB4和α2(I)-CB3,5所代表的未还原、不溶性牛皮胶原蛋白区域参与了不可还原的酸稳定型和成熟型交联的形成。在牛皮的不溶性胶原蛋白中，发现可溶性I型胶原蛋白中CNBr肽的特征比例发生了变化。在十二烷基硫酸钠聚丙烯酰胺凝胶电泳中显示的α1(I)-CB6、α2(I)-CB4和α2(I)-CB3,5条带的强度在这类样品中显著降低，这表明这些肽参与了交联形成。还对纯化的高聚合CNBr肽级分进行了研究，以确认I型胶原蛋白的α2链参与了成熟交联的形成。这种物质的胰凝乳蛋白酶消化产物含有源自α2(I)-CB4、α2(I)-CB3,5和α1(I)-CB6的肽。最后，仔细筛选交联物质的酸水解产物，以检测低至千分之一氨基酸浓度的交联物。仅检测到两种化合物，一种被鉴定为“羟醛-组氨酸”，另一种是迄今未知的化合物。这些结果表明，α1(I)链和α2(I)链均参与了成熟交联的形成，并且聚合CNBr肽级分包含由迄今未表征的不可还原交联所交联的成分。
