Proteinous Bacterial Cell Wall Lytic Enzyme Inhibitor Produced by Bacteria

从土壤中分离到一株能产生N-乙酰胞壁酶抑制剂的细菌（编号SMK-6024）。该菌株经鉴定为巨大芽孢杆菌（Bacillus megaterium）。经硫酸铵分级沉淀、SP-Sephadex柱层析和Sephacryl S-200凝胶过滤纯化。该抑制剂被命名为LEI。LEI抑制链霉菌的N-乙酰胞壁酶，但不抑制动物和植物来源的溶菌酶。用凝胶过滤法测得LEI的分子量为32，000，用SDSPAGE测得LEI的分子量为16，000。这表明LEI由二聚体组成。等电点为6.7。EI复合物以E_2I_2形式存在。从土壤中分离到一株产卵白色溶菌酶抑制剂的细菌（编号I-139）。经硫酸铵分级沉淀、DEAE-Sephadex、Sephacry S-200或DEAE-Toyoprotein柱层析和固定化卵白色溶菌酶亲和层析纯化。I-139对动物溶菌酶如鸡蛋白色溶菌酶和人乳溶菌酶有抑制作用，但对植物溶菌酶和微生物来源的N-乙酰胞壁酶无抑制作用。纯化的I-139含有脂质。通过有机溶剂除去该脂质。该抑制剂的分子量估计为14，000。抑制剂中主要氨基酸为亮氨酸、天冬氨酸、瓦尔和谷氨酸。

A bacterium (No.SMK-6024) which produced N-acetylmuramidase inhibitor was isolated from soil. This strain was identified as Bacillus megaterium. The inhibitor was purified by ammonium sulfate fractionation, SP-Sephadex column chromatography and Sephacryl S-200 gel filtration. The inhibitor was named as LEI. LEI inhibited N-acetylmuramidase from Streptomyces but did not inhibit lysozyme from animal and plant origin. Molecular weight of LEI was estimated as 32,000 by gel filtration and as 16,000 by SDSPAGE. This indicated that LEI consisted of dimer. Isoelectric point was 6.7. EI complex exsisted as E_2I_2.A bacterium (No.I-139) which produced egg white lysozyme inhibitor was isolated form soil. The inhibitor was purified by ammonium sulfate fractionation, column chromatography by DEAE-Sephadex, Sephacry S-200 or DEAE-Toyopearl, and affinity chromatography by immobilized egg white lysozyme. The inhibitor was named as I-139 I-139 inhibited animal lysozyme such as egg white lysozymes and human milk lysozyme, but did not inhibit plant lysozyme and N-acetylmuramidase from microbilal origin. Purified I-139 contained lipid. This lipid was removed by organic solvent. The molecular weight of this inhibitor was estimated as 14,000. Leu, Asp, Val and Glu were main amino acids in the inhibitor.