Keil-Dlouha V, Keil B
Biochim Biophys Acta. 1978 Jan 12;522(1):218-28. doi: 10.1016/0005-2744(78)90337-6.
The highly active form of collagenase (EC 3.4.24.3) from Achromobacter iophagus (specific activity 2 microkat/mg) has a molecular weight of 70,000 and the sedimentation coefficient s20,2 = 4.4 S. It is composed of two subunits of molecular weight 35,000 and s20,w of 2.9 S. The dissociation of the dimer under different conditions resulted in the complete and irreversible loss of enzymic activity. A unique N-terminal sequence Thr-Ala-Ala-Asp-Leu-Glu-Ala-Leu-Val- indicates that the two subunits are identical, at least in the N-terminal part of the polypeptide chain. Reduction and pyridylethylation of the subunit change neither molecular weight nor amino acid composition: therefore each subunit of molecular weight 35,000 consists of a single polypeptide chain. Another active and homogeneous form of Achromobacter collagenase (specific activity 1.64 microkat/mg) gives a value for the apparent molecular weight of 80,000 on sodium dodecyl sulphate-polyacrylamide electrophoresis. It is also a dimer in which each of the two subunits of molecular weight 35,000 binds non-covalently a peptide of molecular weight 5000. The dissociation of this form of collagenase is also accompanied by irreversible loss of enzymic activity. The amino acid composition of the subunits which were isolated from both 70,000 and 80,000 collagenases is the same. The role of dimer-monometer equilibrium in the biological function of collagenase is discussed.
食油无色杆菌来源的高活性胶原酶（EC 3.4.24.3，比活性为2微卡特/毫克）分子量为70,000，沉降系数s20,2为4.4 S。它由两个分子量为35,000、s20,w为2.9 S的亚基组成。在不同条件下二聚体的解离导致酶活性完全不可逆丧失。独特的N端序列苏氨酸-丙氨酸-丙氨酸-天冬氨酸-亮氨酸-谷氨酸-丙氨酸-亮氨酸-缬氨酸-表明这两个亚基是相同的，至少在多肽链的N端部分是相同的。亚基的还原和吡啶基乙基化既不改变分子量也不改变氨基酸组成：因此每个分子量为35,000的亚基由一条单一的多肽链组成。食油无色杆菌胶原酶的另一种活性且均一的形式（比活性为1.64微卡特/毫克）在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上给出的表观分子量为80,000。它也是一种二聚体，其中两个分子量为35,000的亚基各自非共价结合一个分子量为5000的肽段。这种形式的胶原酶解离也伴随着酶活性的不可逆丧失。从70,000和80,000胶原酶中分离得到的亚基的氨基酸组成相同。文中讨论了二聚体-单体平衡在胶原酶生物学功能中的作用。
