Immobilization of IMP-1 metallo-beta-lactamase: the promising approach for the removal of beta-lactam antibiotics

Metallo-beta-lactamase enzymes are produced by some bacteria which can hydrolyze beta-lactam antibiotics such as penicillins, cephalosporins, cephamycins, and carbapenems. As a result, these enzymes cause bacteria resistance to these antibiotics. In this study, for the first time, IMP-1 metallo-beta-lactamases enzyme was immobilized on CNBr-activated sepharose through covalent bonding. The optimum temperatures of enzyme activity for free and immobilized enzymes were 70 degrees C and 60 degrees C. The optimum pH of IMP-1 activity was 7.5 that after immobilization, changed to 6.5. Due to enzyme immobilization, Km and Vmax values were decreased from 727.9 to 230.5 mu mol and from 71.47 to 10.76 mu mol/min for penicillin G as substrate. After 20 reaction cycles, 75% of the enzyme activity was retained, according to a reusability analysis of the immobilized enzyme. Furthermore, as compared to free enzyme, the thermal and storage stability of immobilized enzyme was reduced. Consequently, immobilization of IMP-1 by covalent binding on carriers suitable as a