Tsunasawa S, Masaki T, Hirose M, Soejima M, Sakiyama F
Institute for Protein Research, Osaka University, Japan.
J Biol Chem. 1989 Mar 5;264(7):3832-9.
The complete amino acid sequence of Achromobacter lyticus protease I (EC 3.4.21.50), which specifically hydrolyzes lysyl peptide bonds, has been established. This has been achieved by sequence analysis of the reduced and S-carboxymethylated protease and of peptides obtained by enzymatic digestion with Achromobacter protease I itself and Staphylococcus aureus V8 protease and by chemical cleavage with cyanogen bromide. The protease consists of 268 residues with three disulfide bonds, which have been assigned to Cys6-Cys216, Cys12-Cys80, and Cys36-Cys58. Comparison of the amino acid sequence of Achromobacter protease and other serine proteases of bacterial and mammalian origins has revealed that Achromobacter protease I is a mammalian-type serine protease of which the catalytic triad comprises His57, Asp113, and Ser194. It has also been shown that the protease has 9- and 26-residue extensions of the peptide chain at the N and C termini, respectively, and overall sequence homology is as low as 20% with bovine trypsin. The presence of a disulfide bridge between the N-terminal extension Cys6 and Cys216 close to the putative active site in the C-terminal region is thought to be responsible for the generation of maximal proteolytic function in the pH range 8.5-10.7 and enhanced stability to denaturation.
已确定溶杆菌属蛋白酶I（EC 3.4.21.50）的完整氨基酸序列，该酶特异性水解赖氨酰肽键。这是通过对还原型和S-羧甲基化蛋白酶以及用溶杆菌属蛋白酶I自身、金黄色葡萄球菌V8蛋白酶进行酶解和用溴化氰进行化学裂解得到的肽段进行序列分析实现的。该蛋白酶由268个残基组成，有三个二硫键，分别位于Cys6-Cys216、Cys12-Cys80和Cys36-Cys58。对溶杆菌属蛋白酶与其他细菌和哺乳动物来源的丝氨酸蛋白酶的氨基酸序列比较表明，溶杆菌属蛋白酶I是一种哺乳动物型丝氨酸蛋白酶，其催化三联体由His57、Asp113和Ser194组成。还表明该蛋白酶在N端和C端分别有9个和26个残基的肽链延伸，与牛胰蛋白酶的总体序列同源性低至20%。N端延伸的Cys6与靠近C端区域假定活性位点的Cys216之间存在二硫桥，被认为是在pH 8.5-10.7范围内产生最大蛋白水解功能和增强对变性稳定性的原因。
