A. M. Luhavaya, V. G. Grigorenko Study of catalytic properties of recombinant class A TEM-1 b-lactamase and its iNhibition by sulbactam, tazobactam and clavulanic acid Abstract In this work was studied homogeneous preparation of recombinant class A TEM-1 b-lactamase; kinetic parameters obtained with chromogenic substrate CENTA are as follows: KM = 22 mM, V = 0,39 mM/s, kcat = 31,2 s-1, kcat/KM =1,4 mM-1s-1. Based on the comparison of determined Michaelis constant (KM = 22 mM) with literature data it is approved that recombinant enzyme is about 3 times more specific against CENTA than the native one (KM = 70 mM). It was ascertained competitive type of inhibition for sulbactam, tazobactam and clavulanic acid. For the first time the inhibition constants for recombinant b-lactamase TEM-1 with CENTA as a substrate for sulbactam, tazobactam, clavulanic acid (KI(sulbactam) = 0,43 mM, KI(tazobactam) = 0,041 mM, KI(clavulanic acid) = 0,046 mM) have been determined. It was shown that tazobactam and clavulanic acid are the most effective inhibitors for the recombinant b-lactamase as having the least value of KI and their inactivation influence can be accepted as identical.
Copyright (C) Chemistry Dept., Moscow State University, 2002 |
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