Department of Chemistry and Biochemistry, Baylor University, Waco, TX 76798-7348, USA.
Biotechnol Lett. 2011 Jul;33(7):1417-22. doi: 10.1007/s10529-011-0569-9. Epub 2011 Mar 3.
Metallo-β-lactamase from Bacillus anthracis (Bla2) catalyzes the hydrolysis of β-lactam antibiotics which are commonly prescribed to combat bacterial infections. Bla2 contributes to the antibiotic resistance of this bacterium. An understanding of it is necessary to design potential inhibitors that can be introduced with current antibiotics for effective eradication of anthrax infections. We have purified Bla2 using Ni(2+)-affinity chromatography with over 140-fold increase in activity with a yield of 3.5%. The final specific activity was 19,000 units/mg. Purified Bla2 displays different K ( m ), V ( max ), and (k ( cat ) /K (M)) with penicillin G and cephalexin as substrates and is also sensitive to pH, with maximum activity between pH 7.0-9.0. The IC(50) (50% inhibition concentration) value of EDTA against Bla2 is 630 nM, which can be understood by observing its three-dimensional interaction with the enzyme.
炭疽杆菌金属β-内酰胺酶（Bla2）能够催化β-内酰胺类抗生素的水解，这类抗生素常用于治疗细菌感染。Bla2 导致了该细菌对抗生素的耐药性。为了设计潜在的抑制剂，我们需要了解它的结构，这种抑制剂可以与现有的抗生素一起使用，以有效消除炭疽感染。我们使用 Ni(2+)-亲和层析法对 Bla2 进行了纯化，酶活提高了 140 多倍，收率为 3.5%。最终比活为 19,000 单位/毫克。纯化后的 Bla2 对青霉素 G 和头孢氨苄作为底物显示出不同的 K ( m )、V ( max ) 和 (k ( cat )/K (M))，并且对 pH 敏感，最适 pH 范围为 7.0-9.0。EDTA 对 Bla2 的 IC 50 值（50%抑制浓度）为 630 nM，可以通过观察其与酶的三维相互作用来理解。
