Papaioannou S E, Marsheck W J
Thromb Haemost. 1977 Jun 30;37(3):556-65.
An extracellular protease SN 687, secreted by the soil bacterium isolate WM 122, has been purified by means of gel filtration, ammonium sulfate precipitation, DEAE-Sephadex and hydroxylapatite chromatography. Apparent homogeneity was ascertained by polyacrylamide gel electrophoresis. The protease was inactivated by ethylenediamine tetracetic acid (EDTA) but not by diisopropylfluorophosphate (DFP), and it was partially inhibited by serum inhibitors. SN 687 was shown to be of high specific activity against casein and fibrin, but it did not hydrolyze L-lysine-methyl ester dihydrochloride (LME), p-tosyl-L-arginine-methyl ester hydrochloride (TAME) and N-benzoyl-L-tyrosine-ethyl ester hydrochloride (BTEE) synthetic substrates. The optimum pH for hydrolysis of casein was 7.5 and the molecular weight, as determined by gel filtration, was 31,000.
土壤细菌分离株WM 122分泌的一种细胞外蛋白酶SN 687，已通过凝胶过滤、硫酸铵沉淀、DEAE-葡聚糖凝胶和羟基磷灰石色谱法进行了纯化。通过聚丙烯酰胺凝胶电泳确定其具有明显的均一性。该蛋白酶被乙二胺四乙酸（EDTA）灭活，但不被二异丙基氟磷酸酯（DFP）灭活，并且它被血清抑制剂部分抑制。已证明SN 687对酪蛋白和纤维蛋白具有高比活性，但它不水解L-赖氨酸甲酯二盐酸盐（LME）、对甲苯磺酰-L-精氨酸甲酯盐酸盐（TAME）和N-苯甲酰-L-酪氨酸乙酯盐酸盐（BTEE）等合成底物。酪蛋白水解的最佳pH值为7.5，通过凝胶过滤测定的分子量为31,000。
