Duksin D, Bornstein P
J Biol Chem. 1977 Feb 10;252(3):955-62.
Tunicamycin, an inhibitor of lipid carrier-dependent protein glycosylation, was used in studies of procollagen synthesis, secretion, and proteolytic modification by chick cranial bones in organ culture and by chick tendon fibroblasts in tissue culture. Tunicamycin inhibited the incorporation of D-[2-3H]mannose into procollagen by greater than 90% whereas general protein synthesis and collagen synthesis were decreased by only 10 to 20%. The procollagen synthesized in the presence of tunicamycin was secreted normally and its immunological characteristics, as detected by an antiserum to the intact protein, were unchanged. However, tunicamycin caused an accumulation of biosynthetic intermediates containing disulfide-bonded COOH-terminal extensions in both cell and bone culture. Cleavage of NH2-terminal extensions was not detectably impaired. These findings provide additional support for the involvement of more than one enzyme in the limited proteolytic conversion of procollagen to collagen.
衣霉素是一种脂质载体依赖性蛋白糖基化抑制剂，用于研究器官培养中的鸡颅骨和组织培养中的鸡肌腱成纤维细胞对前胶原的合成、分泌及蛋白水解修饰。衣霉素抑制D-[2-³H]甘露糖掺入前胶原的比例超过90%，而总蛋白合成和胶原合成仅减少10%至20%。在衣霉素存在下合成的前胶原能正常分泌，用针对完整蛋白的抗血清检测，其免疫学特性未发生改变。然而，衣霉素在细胞培养和骨培养中均导致了含有二硫键连接的COOH末端延伸的生物合成中间体的积累。NH₂末端延伸的切割未受到可检测到的损害。这些发现为前胶原向胶原的有限蛋白水解转化过程中涉及多种酶提供了更多支持。
