Little C, Emanuel E L, Gagnon J, Waley S G
Biochem J. 1986 Nov 15;240(1):215-9. doi: 10.1042/bj2400215.
Beta-lactamases are divided into classes A, B and C on the basis of their amino acid sequences. Beta-Lactamases were incubated at pH 4.0 with the carboxy-group reagent 1-(3-dimethylaminopropyl)-3-ethylcarbodi-imide plus a coloured nucleophile and the extents of inactivation and nucleophile incorporation were monitored. Two class A enzymes (from Bacillus cereus and Bacillus licheniformis) and two class C enzymes (from Enterobacter cloacae P99 and Pseudomonas aeruginosa) were examined. All four enzymes were inactivated, with total inactivation corresponding to the incorporation of approx. 2-3 mol of nucleophile/mol of enzyme. In the case of beta-lactamase I from Bacillus cereus, some 53% of the incorporated nucleophile was located on glutamic acid-168 in the amino acid sequence.
β-内酰胺酶根据其氨基酸序列分为A、B和C类。将β-内酰胺酶在pH 4.0条件下与羧基试剂1-(3-二甲基氨基丙基)-3-乙基碳二亚胺以及一种带色亲核试剂一起温育，并监测失活程度和亲核试剂掺入情况。检测了两种A类酶（来自蜡样芽孢杆菌和地衣芽孢杆菌）和两种C类酶（来自阴沟肠杆菌P99和铜绿假单胞菌）。所有四种酶均被失活，完全失活对应于每摩尔酶掺入约2 - 3摩尔亲核试剂。就蜡样芽孢杆菌的β-内酰胺酶I而言，掺入的亲核试剂约53%位于氨基酸序列中的谷氨酸-168上。
