TEM x Tubulin

Because of the need for control of beta-lactamase-mediated resistance and the recent development of tazobactam, the author has examined the inhibitors of various beta-lactamases for their effectiveness. On the basis of the kinetic data, tazobactam exhibited the highest affinity to various beta-lactamases. A combination with tazobactam was found to enhance the effectiveness of piperacillin against S. aureus producing penicillinase, E. coli producing TEM-1 or TEM 2 enzymes and class I beta-lactamase-derepressed isolates of E. cloacae, Serratia spp. and C. freundii, however not P. aeruginosa, while there was no marked synergism in beta-lactamase-derepressed clones of K. oxytoca.

The lipo-penicillinase (LIPEN) gene from an alkalophilic Bacillus sp. strain 170 was cloned in Escherichia coli using the vector pHSG399. A plasmid, pFAP121, was isolated from an ampicillin resistant transformant and the cloned LIPEN gene was found to be in a 2.2 kb DNA fragment. The nucleotide sequence of a 1.9 kb segment encoding the LIPEN was determined. This segment showed an open reading frame which would encode a polypeptide of 310 amino acids. The amino acid sequence of this LIPEN gene product has strong homology with those of the Bacillus cereus beta-lactamase III and Bacillus licheniformis penicillinase.