Clostridium histolyticum collagenases: a new look at some old enzymes.
Clostridium histolyticum collagenases: a new look at some old enzymes.
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发表时间：
1992
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通讯作者：
Mookhtiar Ka;V. He
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作者：
Mookhtiar Ka;V. He
由字母α、β、γ、δ、β、ζ和η表示的七种胶原酶已从溶组织梭菌的培养滤液中纯化至均一。所有七种酶都是锌蛋白酶，其活性需要钙离子，并且具有必需的羧基、酪氨酰和赖氨酰残基。这些酶可以根据它们的多肽链中的序列同源性分为两类，如从它们的胰蛋白酶的比较中所揭示的。这种分类也支持他们对肽底物的特异性，他们与底物类似物抑制剂的相互作用，以及他们的攻击模式的三螺旋胶原蛋白的比较。这些酶的序列特异性已被详细研究。这两个类别的特性相似，但互补。这两类都表现出内肽酶和三肽羧肽酶活性，其中后者被认为有助于从胶原片段的C-末端去除Gly-X-Y三联体。这些胶原酶对三螺旋I型、II型和III型胶原的攻击模式对于每类内的酶而言非常相似，但对于两类而言不同。I类酶首先水解这些胶原蛋白分子的三螺旋结构域末端附近的位点，而II类酶在内部进行初始裂解。这些初始裂解的位点正在测序，初步结果表明，它们在亚氨基酸含量或分布方面与组织胶原酶裂解位点不相似。已经测量了I、II和III型胶原蛋白水解的动力学参数，并且其量级与组织胶原酶的相似。合成肽底物类似物抑制剂已被制备用于两类胶原酶，并显示为过渡态类似物抑制剂。
Seven collagenases denoted by the letters alpha, beta, gamma, delta, epsilon, zeta and eta have been purified to homogeneity from the culture filtrate of Clostridium histolyticum. All seven enzymes are zinc proteinases that require calcium ions for activity and have essential carboxyl, tyrosyl and lysyl residues. These enzymes can be divided into two classes on the basis of the sequence homologies in their polypeptide chains, as revealed from a comparison of their tryptic digests. This division into classes is also supported by a comparison of their specificities toward peptide substrates, their interaction with substrate-analog inhibitors, and their mode of attack of triple helical collagens. The sequence specificities of these enzymes have been studied in detail. The specificities of the two classes are similar, but complementary. Both classes exhibit both endopeptidase and tripeptidylcarboxypeptidase activities, where the latter is thought to facilitate removal of Gly-X-Y triplets from the C-terminus of collagen fragments. The mode of attack of these collagenases on triple helical type I, II and III collagens is very similar for the enzymes within each class, but different for the two classes. The class I enzymes first hydrolyze loci near the ends of the triple helical domains of these collagen molecules, while the class II enzymes make their initial cleavages in the interior. The sites of these initial cleavages are being sequenced and preliminary results indicate that they do not resemble the tissue collagenase cleavage site with respect to either their imino acid content or distribution. The kinetic parameters for the hydrolysis of type I, II and III collagens have been measured and are similar in magnitude to those for the tissue collagenases. Synthetic peptide substrate-analog inhibitors have been prepared for both classes of collagenases and shown to be transition-state-analog inhibitors.