Bicknell R, Emanuel E L, Gagnon J, Waley S G
Biochem J. 1985 Aug 1;229(3):791-7. doi: 10.1042/bj2290791.
The production and purification of a tetrameric zinc beta-lactamase from Pseudomonas maltophilia IID 1275 were greatly improved. Three charge variants were isolated by chromatofocusing. The subunits each contain two atomic proportions of zinc and (in two of the variants) one residue of cysteine. The thiol group is not required for activity, nor does it appear to bind to the metal. Replacement of zinc by cobalt, cadmium or nickel takes place at a measurable rate, and gives enzymes that are less active than the zinc enzyme. The properties of this enzyme differ from those of the other known zinc beta-lactamase, beta-lactamase II from Bacillus cereus. The amino acid sequence of the N-terminal 32 residues was determined; there is no similarity to the N-terminal sequences of other beta-lactamases.
嗜麦芽窄食单胞菌IID 1275四聚体锌β-内酰胺酶的生产和纯化得到了极大改进。通过色谱聚焦分离出了三种电荷变体。每个亚基含有两个原子比例的锌以及（在其中两个变体中）一个半胱氨酸残基。硫醇基团对于活性并非必需，而且似乎也不与金属结合。钴、镉或镍取代锌的过程以可测量的速率发生，并且产生的酶活性低于锌酶。这种酶的特性不同于其他已知的锌β-内酰胺酶，即蜡状芽孢杆菌的β-内酰胺酶II。测定了N端32个残基的氨基酸序列；与其他β-内酰胺酶的N端序列没有相似性。
