摘要
本文对临床分离的脆弱拟杆菌(Bacteroides fragilis)55的β-内酰胺酶进行了理化及酶学特性的研究。该酶为非诱导性,以头胞菌素酶活性为主,分子量为43000,等电点 pI 为4.95,酶反应最适 pH 为7.2,最适温变为37℃。该酶对各种底物的 K_m(μmol/L)值为:头孢噻吩185,头孢噻啶103、头孢唑淋200,头孢羟唑263、头孢氧哌羟苯唑830。对各种底物的相对水解率为头孢羟唑>头孢噻吩>头孢唑啉>头孢噻啶>头孢氧哌羟苯唑>青霉素>氨苄青霉素>头霉甲氧噻吩>羟羧氧酰胺菌素。该酶对羧苄青霉素、头霉甲氧噻吩捧酸、青霉烷砜、对氯安息香酸汞及邻氯青霉素的抑制作用敏感。
Bacteroides fragilis 55 from clinical spe-cimens was selected at random for β-lacta-mase investigation of physico-chemical andenzymological properties.The enzyme wascharacterized as a cell-associated cephalospo-rinase with some penicillinase activity,themolecular weight of the enzyme being 43000and the pl 4.95.It could be inhibited bycefoxitin,PCMB,carbenicillin,sulbactam,clavulanic acid and cloxacillin.The optimumpH and temperature for enzyme reactionshave been found to be 7.2 and 37℃,respecti-vely.The analysis of amino acid compositionand paremeters of enzyme kinetics has beendescribed.
出处
《微生物学报》
CAS
CSCD
北大核心
1990年第6期433-437,共5页
Acta Microbiologica Sinica
关键词
脆弱拟杆菌
Β内酰胺酶
酶促动力学
Bacteroides fragilis
β-Lactaniase
Enzyme reaction kinetics
