نتایج جستجو برای: penicillin g acylase
تعداد نتایج: 453817 فیلتر نتایج به سال:
Penicillin G acylase (PA) is an important enzyme used in the industrial production of b-lactam antibiotics. In this study, the effects of mutations in the translation initiation region of the Escherichia coli pac gene, encoding periplasmic PA, were examined. Several mutations led to increased amounts of PA activity, including those that lengthened the spacer region between the ribosome binding ...
Semi-synthetic β-lactam antibiotics are synthesized enzymatically with the use of penicillin G acylase (PGA). Currently, PGA only exhibits weak diastereoselectivity with respect to the alpha amino group of rac-phenylglycine methyl ester (rac-PGME) when it is coupled with 6-aminopenicillanic acid to synthesize ampicillin. Therefore, we sought to improve the diastereoselectivity of PGA by targeti...
Entrapment of permeabilized whole cells within a matrix is a common method for immobilization. Chitosan possesses distinct chemical and biological properties, which make it a suitable matrix for entrapment and immobilization of penicillin G acylase (PGA). In the first step, Escherichia coli (ATCC 11105) cells were permeabilized using N-cetyl-N,N,N-trimethyl ammonium bromide (CTAB) (0.1% w/v, 45...
A new mutant of the industrial enzyme penicillin G acylase (PGA) from Escherichia coli has been designed to improve its reversible immobilization on anionic exchangers (DEAE- or polyethyleneimine [PEI]-coated agarose) by assembling eight new glutamic residues distributed homogeneously through the enzyme surface via site-directed mutagenesis. The mutant PGA is produced and processed in vivo as i...
This work reports the influence of different culture preservation methods on the production of penicillin G acylase (PGA) by Bacillus megaterium ATCC 14945. The initial stock culture, presenting PGA activity of 97 IU l, was preserved for two years using different procedures: monthly subculturing and storage in refrigerator (S), freeze-drying using skim milk 10%, plus inositol 5% as cryoprotecto...
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