Kao W W
Curr Eye Res. 1985 Feb;4(2):79-86. doi: 10.3109/02713688508999972.
Corneas and tendons dissected from 17-day-old chick embryos were labeled with [35S]methionine in the presence of 0.3 mM alpha,alpha'-dipyridyl. The unhydroxylated, 35S-labeled pro alpha chains and alpha chains were isolated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The pro alpha and alpha chains were then subjected to peptide-map analysis by proteolytic digestion with trypsin and alpha-chymotrypsin, papain or proteinase K. The peptide-maps derived from cornea and tendon pro alpha 1(I) chains are identical. Similar results were obtained from cornea and tendon alpha 1(I) chains. There were differences in the peptide maps derived from cornea and tendon pro alpha 2(I) chains. However, no difference was observed in alpha 2(I) chains. These results suggest that cornea and tendon pro alpha 1(I) chains are probably identical in primary structures, whereas the cornea pro alpha 2(I) chain may be different from the tendon pro alpha 2(I) chain within pepsin sensitive regions of the procollagen molecule. The reason for difference in the peptide-maps of pro alpha 2(I) chains remain unknown. One of the possible explanations is the variation of posttranslational modification within the propeptides of the pro alpha 2(I) chain. However, this hypothesis needs to be further investigated. Nevertheless, the finding that the peptide-maps of alpha 2(I) chains from tendons and corneas are identical fail to support the two genes hypothesis for pro alpha 2(I) chains.
从17日龄鸡胚中分离出的角膜和肌腱在0.3 mM α,α'-联吡啶存在的情况下用[35S]甲硫氨酸进行标记。未羟化的、35S标记的前α链和α链通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳进行分离。然后，前α链和α链通过用胰蛋白酶、α-糜蛋白酶、木瓜蛋白酶或蛋白酶K进行蛋白水解消化来进行肽图谱分析。源自角膜和肌腱前α1(I)链的肽图谱是相同的。从角膜和肌腱α1(I)链也获得了类似的结果。源自角膜和肌腱前α2(I)链的肽图谱存在差异。然而，在α2(I)链中未观察到差异。这些结果表明，角膜和肌腱前α1(I)链在一级结构上可能是相同的，而角膜前α2(I)链在原胶原分子的胃蛋白酶敏感区域内可能与肌腱前α2(I)链不同。前α2(I)链肽图谱差异的原因仍然未知。一种可能的解释是前α2(I)链前肽内翻译后修饰的变化。然而，这一假设需要进一步研究。尽管如此，肌腱和角膜α2(I)链肽图谱相同的发现并不支持前α2(I)链的双基因假说。
