title: Interaction of beta-iodopenicillanate with the beta-lactamases of Streptomyces albus G and Actinomadura R39.
abstract: The beta-lactamases of Streptomyces albus G and Actinomadura R39 are inactivated by beta-iodopenicillanate. However, in contrast with the beta-lactamase I from Bacillus cereus, they also efficiently catalyse the hydrolysis of the inactivator; with the S. albus G enzyme, kcat. is larger than 25s-1 and the number of turnovers before inactivation is 515. With the A. R39 enzyme, kcat. is larger than 50s-1 and the number of turnovers before inactivation is 80. After hydrolysis of the beta-lactam amide bond, the product rearranges into 2.3-dihydro-2,2-dimethyl-1,4-thiazine-3,6-dicarboxylate, which exhibits an absorption maximum at 305 nm.
mesh_terms: D000191:Actinomycetaceae / Q000201:enzymology*; D006868:Hydrolysis; D007700:Kinetics; D013058:Mass Spectrometry; D008954:Models, Biological; D010397:Penicillanic Acid / Q000378:metabolism* / Q000031:analogs & derivatives; D013302:Streptomyces / Q000201:enzymology*; D065093:beta-Lactamase Inhibitors
chemical_list: D065093:beta-Lactamase Inhibitors; D010397:Penicillanic Acid; C031528:6-iodopenicillanic acid