Three mutations on the penicillin acylase surface (increasing the number of Lys in a defined area) were performed. They did not alter the enzyme's stability and kinetic properties; however, after immobilization on glyoxyl-agarose, the mutant enzyme showed improved stability under all tested conditions (e.g., pH 2.5 at 4 degrees C, pH 5 at 60 degrees C, pH 7 at 55 degrees C, or 60% dimethylforma...

N-Acylhomoserine lactone acylase (AHL acylase) is a well-known enzyme responsible for disrupting cell-cell communication (quorum sensing) in bacteria. Here, we isolated and characterized a novel and unique AHL acylase (designated MacQ) from a multidrug-resistant bacterium, Acidovorax sp. strain MR-S7. The purified MacQ protein heterologously expressed in Escherichia coli degraded a wide variety...

A new crystal form of penicillin acylase (penicillin amidohydrolase, E.C. 3.5.1.11) from Escherichia coli W (ATCC 11105) is reported. The crystals were grown using a combination of hanging-drop and streak-seeding methods. The crystals are in the monoclinic space group P2(1) with cell dimensions a = 51.52, b = 131.95, c = 64.43 A, beta = 106.12 degrees. There is one heterodimer in the asymmetric...

The different ionic molecules/compounds were used as a ligand for the immobilization of penicillin G acylase on the highly porous cellulose-based polymeric membrane having buffer flux 1,746 LMH (L m(-2) h(-1)) at 0.5 bar pressure. The immobilized enzyme activity around 250 U(App) was obtained with the ligand such as proline, tryptophan, casein acid hydrolysate, and brilliant green. Comparativel...

An experimental design was applied to improve the reaction conditions for enzymatic synthesis of ampicillin from phenylglycine methyl ester (PGME) and 6-aminopenicillanic acid (6-APA), catalyzed by penicillin G acylase from E. coli immobilized on an agarose-glyoxyl derivative. The presence and magnitude of interactions between reaction variables were estimated using a 2 factorial design. A batc...

The site of reaction of penicillin acylase from Kluyvera citrophila with the potent inhibitor phenylmethanesulphonyl fluoride was investigated by incubating the inactivated enzyme with thioacetic acid to convert the side chain of the putative active-site serine residue to that of cysteine. The protein product contained one thiol group, which was reactive towards 2,2'-dipyridyl disulphide and io...