title: Analytical isoelectric focusing of R factor-determined beta-lactamases: correlation with plasmid compatibility.
abstract: R factor-determined beta-lactamases have been investigated by analytical isoelectric focusing. The enzymes such as those specified by the R6K and RP4 plasmids (TEM-type enzymes) are notably homogenous in biochemical tests (Hedges et al., 1974), but two subclasses can be distinguished by isoelectric focusing. Three subclasses can be distinguished among the oxacillin-hydrolyzing enzymes, in good agreement with the classification based upon biochemical characteristics (Dale and Smith, 1974). The TEM-type beta-lactamases are promiscuously distributed among plasmids of a wide variety of compatibility groups, whereas the various oxacillin-hydrolyzing enzymes show some degree of correlation with compatibility.
mesh_terms: D000667:Ampicillin / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology; D007525:Isoelectric Focusing; D010068:Oxacillin / Q000494:pharmacology; D010403:Penicillin Resistance; D010405:Penicillinase / Q000145:classification*; D011815:R Factors
chemical_list: D000667:Ampicillin; D010405:Penicillinase; D010068:Oxacillin