Penicillin amidase

About: Penicillin amidase is a research topic. Over the lifetime, 576 publications have been published within this topic receiving 15563 citations. The topic is also known as: penicillin amidohydrolase & ampicillin acylase.

Kinetic studies of penicillin G hydrolysis with immobilized penicillin acylase in an electrodialyzer

Abstract: A reactor-separator combining immobilized penicillin acylase (IPA) and electrodialysis was developed for the production of 6-aminopenicillanicacid (6-APA)from the enzymatic hydrolysis of penicillin G (Pen-G) accompanying the continuous removal of by-product phenylacetic acid (PAA). The kinetics of Pen-G hydrolysis by IPA, the separation of PAA, 6-APA and Pen-G with electrodialysis, as well as the reaction-separation phenomena of Pen-G hydrolysis with IPA in the electrodialyzer were studied. The products inhibition mechanism and rate equation of Pen-G hydrolysis by IPA were obtained. The separation of PAA, 6-APA and Pen-G with electrodialysis was dependent on their molecular size and affinity toward the anion exchange membrane. The transport rates of three components decreased in the sequence PAA > 6-APA > Pen-G. Strong concentration polarization of Pen-G was observed in the vicinity of anion exchange membrane. An increase in Pen-G concentration enhanced the selectivity factor of PAA to 6-APA but ...

Immobilization of whole Escherichia coli containing penicillin amidase using cross-linking agents and fillers

Abstract: To obtain a catalyst with good mechanical stress stability and other operational characteristics, cross-linked aggregates of whole Escherichia coli containing penicillin amidase were reinforced with surface modified precipitated silica and chitosan. The immobilized cells plus mixed fillers possess better performance characteristics i.e. higher stability at 4°C and 30°C, least protein leaching capacity and good settling characteristics. Most suitable conditions to prepare catalyst with mixed fillers were: chitosan, 0.3: silica, 0.2 g/g d.wt cell; and minimum moisture content in catalyst, 30% (w/w).

Study of E. coli penicillin amidase. The pH dependence of the equilibrium constant of the enzymatic hydrolysis of benzylpenicillin

Abstract: The equilibrium constant for penicillin amidase-catalyzed hydrolysis of benzylpenicillin(Keg =3.00 +/- 0.24 x 10(-3) M at pH 5.0) and the ionization constants for phenylacetic acid (PAA) and the amino groups of 6-aminopenicillanic acid (6-APA) were determined (4.20 and 4.60 under conditions of the kinetic experiments respectively). The experimental data at pH 6.0 satisfactorily correlated with the theoretical pH-dependence for Keg constructed according to the hypothesis that benzylpenicillin synthesis has a thermodynamic optimum at pH 4.4 equal to a half-sum of the pK values for the carboxylic and amino groups of the PAA and 6-APA respectively.

Enzymatic conversion of benzylpenicillin to 6-aminopenicillanic acid in concentrated ultrafiltered broths

Abstract: Benzylpenicillin filtered broths purified by ultrafiltration and fermented broths clarified by ultrafiltration and afterwards concentrated by reverse osmosis were used directly for enzymatic conversion of benzylpenicillin to 6-aminopenicillanic acid and phenylacetic acid by immobilised penicillin G acylase or amidase. It was concluded that, when the ultrafiltration operation retained 100% of protein, the concentrates from reverse osmosis could be successfully directly fed to the enzymatic reactor, giving high enzymatic conversion yield of benzylpenicillin to 6-aminopenicillanic acid.

Evidence for the involvement of arginyl residue at the active site of penicillin G acylase from Kluyvera citrophila.

Abstract: Penicillin G acylase (PGA) is used for the commercial production of semi-synthetic penicillins. It hydrolyses the amide bond in penicillin producing 6-aminopenicillanic acid and phenylacetate. 6-Aminopenicillanic acid, having the β-lactam nucleus, is the parent compound for all semi-synthetic penicillins. Penicillin G acylase from Kluyvera citrophila was purified and chemically modified to identify the role of arginine in catalysis. Modification with 20 mm phenylglyoxal and 50 mm 2,3-butanedione resulted in 82% and 78% inactivation, respectively. Inactivation was prevented by protection with benzylpenicillin or phenylacetate at 50 mm. The reaction followed psuedo-first order kinetics and the inactivation kinetics (Vmax, Km, and kcat) of native and modified enzyme indicates the essentiality of arginyl residue in catalysis.