Hedberg M, Lindqvist L, Bergman T, Nord C E
Department of Immunology, Microbiology, Pathology, and Infectious Diseases, Huddinge University Hospital, Sweden.
Antimicrob Agents Chemother. 1995 Jul;39(7):1458-61. doi: 10.1128/AAC.39.7.1458.
A beta-lactam-resistant Bacteroides uniformis strain was isolated from a clinical specimen. The strain produced large amounts of beta-lactamase and was resistant to penicillins and cephalosporins. The specific activity of the unpurified beta-lactamase was 4.8 U/mg of protein with nitrocefin as the substrate. The enzyme was purified 188-fold by Q-Sepharose, Sephacryl S-300, and Mono Q column passages. Kinetic parameters of the enzyme were determined by a micromethod performed in microtiter plates. beta-Lactamase was inhibited by cefoxitin and imipenem and hydrolyzed cephalosporins more rapidly than penicillins. The molecular weight was determined by sodium dodecyl sulfate-gradient gel electrophoresis to be 32,500, and the isoelectric point was 4.5.
从一份临床标本中分离出一株对β-内酰胺耐药的单形拟杆菌菌株。该菌株产生大量β-内酰胺酶，对青霉素和头孢菌素耐药。以硝噻吩为底物时，未纯化的β-内酰胺酶的比活性为4.8 U/mg蛋白质。通过Q-琼脂糖凝胶、Sephacryl S-300和Mono Q柱层析，该酶被纯化了188倍。通过在微量滴定板中进行的微量方法测定了该酶的动力学参数。β-内酰胺酶被头孢西丁和亚胺培南抑制，水解头孢菌素的速度比青霉素更快。通过十二烷基硫酸钠梯度凝胶电泳测定其分子量为32,500，等电点为4.5。
