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.

Improved X‐ray diffraction from Bacillus megaterium penicillin G acylase crystals through long cryosoaking dehydration

Abstract: Penicillin G acylase from Bacillus megaterium (BmPGA) is currently used in the pharmaceutical industry as an alternative to PGA from Escherichia coli (EcPGA) for the hydrolysis of penicillin G to produce 6-aminopenicillanic acid (6-APA), a penam nucleus for semisynthetic penicillins. Despite the significant differences in amino-acid sequence between PGAs from Gram-positive and Gram-negative bacteria, a representative PGA structure of Gram-positive origin has never been reported. In this study, crystallization and diffraction studies of BmPGA are described. Poor diffraction patterns with blurred spots at higher resolution were typical for BmPGA crystals cryocooled after a brief immersion in cryoprotectant solution. Overnight soaking in the same cryo-solution substantially improved both the mosaicity and resolution limit through the establishment of a new crystal-packing equilibrium. A crystal of BmPGA diffracted X-rays to 2.20 A resolution and belonged to the monoclinic space group P21 with one molecule of BmPGA in the asymmetric unit.

Chemical mechanism of penicillin V acylase from Streptomyces lavendulae: pH-dependence of kinetic parameters

Abstract: The variation of kinetic parameters of penicillin V acylase from Streptomyces lavendulae with pH was used to gain information about the chemical mechanism of the hydrolysis of penicillin V catalyzed by this enzyme. The pH-dependence of V max showed that a group with a p K value of 6.45 (p K 1 ) must be unprotonated for activity. The pH-dependence of V max / K m showed that a group with a p K value of 7.1 (p K 1 ) must be unprotonated and a group with a p K of 10.83 (p K 2 ) must be protonated for activity. The lower p K value corresponded to a group in the enzyme involved in catalysis and whose protonation state also affects binding. The higher p K value was only involved in binding. Results from chemical modification studies showed the importance of serine residues in the catalytic mechanism of the enzyme and pointed to the identity of the groups responsible for p K 1 and p K 2 as the α-amino nitrogen of the N-terminal residue and a lysine residue, respectively.

Synthesis of beta-lactam antibiotics with immobilized penicillin amidase

Abstract: Beta-lactam antibiotics are synthesized by reacting an amino-beta-lactam component with a corresponding amino-group-containing acylating side-chain component in the presence of penicillin amidase from E. coli covalently immobilized on support particles. The resulting beta-lactam antibiotic product is solubilized by adding an acid such as sulfuric acid to lower the pH to 1.0 at a temperature in the range of 0° C. to +5° C. The immobilized penicillin amidase is substantially inactivated by the acid. After separating the beta-lactam antibiotic product, the immobilized penicillin amidase is substantially reactivated for reuse in antibiotic synthesis by treatment with a buffer having about a neutral pH. Antibiotics that can be produced include ampicillin, amoxicillin, cephalexin, cefaclor and cefadroxil. Support particles that can be used include particles having a macroporous structure and a particle diameter of 10-1000 μm, particles having oxirane groups, particles made of a synthetic polymer and inorganic particles such as porous glass particles.

Antibacterial and toxicological evaluation of beta-lactams synthesized by immobilized beta-lactamase-free penicillin amidase produced by Alcaligenes sp.

Abstract: Search for anti-beta-lactamase and synthesis of newer penicillin were suggested to overcome resistance to penicillin in chemotherapy. It was found that clavulanic acid, an ant-beta-lactamase was ineffective due to its structural modification by bacteria. Thus, there is a need for the synthesis of newer pencillins. Retro-synthesis was inspired by the success of forward reaction i.e.conversion of penicillin G to 6-aminopenicillanic acid (6-APA) by biological process. In the present study a better enzymatic method of synthesis of newer pencillin by a beta-lactamase-free penicillin amidase produced by Alcaligenes sp. is attempted. Antibacterial and toxicological evaluation of the enzymatically synthesized beta-lactams are reported. Condensation of 6-APA with acyl donor was found to be effective when the reaction is run in dimethyl formamide (DMF 50% v/v) in acetate buffer (25 mM pH 5.0) at 37 degrees C. Periplasm entrapped in calcium alginate exihibited the highest yield (approximately 34%) in synthesis. The minimum inhibitory concentration of the synthetic products against Staphylococcus aureus and Salmonella typhi varied between 20-80 microg/ml. Some of the products exhibited antibacterial activity against enteric pathogens. It was interesting to note that product A was potent like penicillin G. LD50 value of three products (product A, B and C) was more than 12 mg/kg. Furthermore, these synthetic beta-lactams did not exihibit any adverse effect on house keeping enzymes viz., serum glutamate oxalacetate-trans-aminase, serum glutamate pyruvate -trans-aminase, acid phosphatase, alkaline phosphatase of the test animals. The hematological profile (RBC and WBC) of the test animals also remained unaffected.