This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Newell, S. L. Articles by Brill, W. J. Search for Related Content PubMed PubMed Citation Articles by Newell, S. L. Articles by Brill, W. J.

Mutants of Salmonella typhimurium That Are Insensitive to Catabolite Repression of Proline Degradation

Department of Bacteriology, College of Agricultural and Life Sciences, University of Wisconsin, Madison, Wisconsin 53706

ABSTRACT

In Salmonella typhimurium the two enzymes of proline catabolism, proline oxidase and ¹-pyrroline-5-carboxylic acid dehydrogenase, are subject to catabolite repression when the cells are grown in the presence of glucose. Mutants partially relieved of catabolite repression (PutR) for the proline catabolic enzymes have been isolated by selection on agar plates containing glucose and proline. The specificity of the catabolite repression-insensitive character for the enzymes of proline utilization has been confirmed by an analysis of other unrelated catabolic enzymes. Histidase and amylomaltase of the mutant strains are equally as sensitive to glucose repression as are the enzymes from the wild type. All four PutR mutants exhibit higher induced and higher basal levels of proline oxidase as compared with the corresponding wild-type levels. The mutations of three strains tested are cotransducible with constitutive, pleiotrophic-negative and structural gene mutations of the put region. Three-factor crosses indicate that two putR mutations are located at one end of the cluster of put mutations.