title: Beta-lactamases from Yersinia enterocolitica.
abstract: Two beta-lactamases, A and B, have been shown to be present in a strain of Yersinia enterocolitica (w222). Beta-Lactamase A hydrolyses a variety of penicillins and cephalosporins. This enzyme is sensitive to thiol reagents, is only partially inhibited by 0-1 mM-cloxacillin and has a molecular weight of approximatley 20,000.beta-Lactamase B shows strong cephalosporinase activity but does not hydrolyse some of the penicillins. It is more resistant than beta-lactamase A to thiol reagents, is completely inhibited by 0-1 mM-cloxacillin and has a molecular weight of about 34,000. With cephaloridine as a substrate, which is readily hydrolysed by both enzymes, about 85% of the total activity of a cell extract is due to beta-lactamase A and 15% to B. Addition of 6-aminopenicillanic acid to the culture during growth results in a 2-to4-fold selective increase in the amount of beta-lactamase B. Two beta-lactamases similar to enzymes A and B have been found in five other strains of Y. enterocolitica. In contrast, only one beta-lactamase, similar to enzyme B, has been detected in a different strain of Y. enterocolitica (H66), which is abnormal in that it is sensitive to ampicillin. Addition of 6-aminopenicillanic acid to cultures of this strain results in an 8-to 10-fold increase in beta-lactamase production.
mesh_terms: D000581:Amidohydrolases; D002474:Cell-Free System; D002510:Cephalosporinase / Q000096:biosynthesis / Q000378:metabolism; D002511:Cephalosporins / Q000378:metabolism; D003023:Cloxacillin / Q000494:pharmacology; D004790:Enzyme Induction; D004791:Enzyme Inhibitors; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007525:Isoelectric Focusing; D008970:Molecular Weight; D010397:Penicillanic Acid / Q000494:pharmacology; D010405:Penicillinase / Q000096:biosynthesis / Q000378:metabolism; D010406:Penicillins / Q000378:metabolism; D013045:Species Specificity; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D015007:Yersinia / Q000201:enzymology*
chemical_list: D002511:Cephalosporins; D004791:Enzyme Inhibitors; D010406:Penicillins; D013439:Sulfhydryl Reagents; D010397:Penicillanic Acid; D000581:Amidohydrolases; D002510:Cephalosporinase; D010405:Penicillinase; D003023:Cloxacillin