title: Regulation of penicillinase synthesis: evidence for a unified model.
abstract: The kinetics of penicillinase induction in Bacillus cereus 569 was investigated. An increase in the rate of penicillinase synthesis was demonstrated within 30 sec of the addition of inducer (benzylpenicillin); however, the maximum induced rate of penicillinase synthesis was not attained until at least 30 min after the addition of inducer. In contrast to earlier claims, a quantitative estimate showed that the penicillinase messenger ribonucleic acid (mRNA) half-life is approximately 2 min. These findings strongly suggest that the rate of synthesis of penicillinase mRNA increases continuously during most of the 30-min latent period. A model for the regulation of penicillinase synthesis in three gram-positive organisms is presented which is consistent with a nondiffusible inducer, a short-lived mRNA, a relatively long latent period (i.e., an apparently slow inactivation of penicillinase repressor), and the existence of at least two regulatory genes.
mesh_terms: D001409:Bacillus cereus / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D002247:Carbon Isotopes; D004790:Enzyme Induction / Q000187:drug effects*; D005796:Genes; D005809:Genes, Regulator; D005827:Genetics, Microbial; D007700:Kinetics; D008954:Models, Biological; D010405:Penicillinase / Q000096:biosynthesis*; D010406:Penicillins / Q000378:metabolism / Q000494:pharmacology; D011523:Protoplasts / Q000201:enzymology; D012333:RNA, Messenger / Q000378:metabolism; D012293:Rifampin / Q000494:pharmacology; D013997:Time Factors
chemical_list: D002247:Carbon Isotopes; D010406:Penicillins; D012333:RNA, Messenger; D010405:Penicillinase; D012293:Rifampin