Procollagen propeptide release by procollagen peptidases and bacterial collagenase.
Procollagen propeptide release by procollagen peptidases and bacterial collagenase.
复制标题
前胶原肽酶和细菌胶原酶释放前胶原前肽。
DOI：
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发表时间：
1979
影响因子：
4.8
通讯作者：
J. Fessler
中科院分区：
文献类型：
--
作者：
N. Morris;L. Fessler;J. Fessler
氨基和羧基原胶原肽酶切割鸡原胶原I，产生完整的氨基前肽和二硫键连接的羧基前肽，这些产物得到了鉴定和部分特性分析。脊椎动物胶原酶产生的原胶原的两个分离片段经这些酶作用也释放出相同的产物，这支持了氨基和羧基前肽的切割可相互独立发生的观点。发现作用于分离底物的酶制剂切割羧基前肽的机制与在整个组织中观察到的机制非常相似。具体而言，羧基原胶原肽酶对正常羟基化的PC胶原进行初次切割是随机的，但对于后续的两次切割，p&1链比p&2链切割得更慢。从体内和体外系统中分离出了羧基切割的中间产物和最终产物。比较表明，胶原链和前肽都没有发生二次后续的蛋白水解切割。部分复性的低羟基化原胶原通过色谱法分离成两部分：根据沉降标准，一部分表现为变性的，另一部分表现为天然的。羧基原胶原肽酶能正确切割天然和变性的物质，而氨基原胶原肽酶只切割天然底物；在胶原螺旋解旋的温度下它就不再起作用。将细菌胶原酶从原胶原中释放含前肽区域的情况与原胶原肽酶的切割进行了比较。氨基前肽内呈胶原螺旋的区域在天然构象下被细菌胶原酶降解得很慢，但变性后则迅速被切割。提出了一个初步模型，其中氨基前肽的末端Co1 1部分折叠回覆盖在胶原主干上。
Amino and carboxyl procollagen peptidases cleaved chick procollagen I to yield the intact amino propeptides and the disulfide-linked carboxyl propeptides, which were identified and partly characterized. The same products were released by these enzymes from the two separated fragments of procollagen produced by vertebrate collagenase, and this supports the concept that cleavage of amino and carboxyl propeptides can occur independently of each other. The mechanism of carboxyl propeptide cleavage by enzyme preparations acting on isolated substrates was found to be closely similar to that observed in whole tissues. Specifically, while carboxyl procollagen peptidase made the initial cut in normally hydroxylated PCcollagen at random, for the subsequent two cuts the p&l chains were cleaved more slowly than the p&2 chain. Intermediates and final products of carboxyl cleavage were isolated from the in viva and in vitro systems. Comparison indicated that neither the collagen chains nor the propeptides underwent secondary, subsequent proteolytic cuts. Partly renatured underhydroxylated procollagen was separated chromatographically into two fractions: one behaved as denatured and the other as native material by sedimentation criteria. While carboxyl procollagen peptidase correctly cleaved both the native and the denatured materials, amino procollagen peptidase only cut the native substrate; it ceased to act at temperatures at which the collagen helix became unfolded. The release of propeptide-containing regions from procollagen by bacterial collagenase was compared with the cleavage by procollagen peptidases. The region within the amino propeptides which is a collagen helix was degraded only slowly by bacterial collagenase while in a native configuration, but was rapidly cleaved after denaturation. A tentative model is proposed in which the terminal Co1 1 portion of the aminopropeptide is folded back over the collagen stem.