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 Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Hagen, D. C. Articles by Magasanik, B. Search for Related Content PubMed PubMed Citation Articles by Hagen, D. C. Articles by Magasanik, B.

Isolation of a trans-Dominant Histidase-Negative Mutant of Salmonella typhimurium

^a Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139

ABSTRACT

A mutation of Salmonella typhimurium was obtained that results in the failure of cells to synthesize the enzyme L-histidine ammonia-lyase (histidase). The mutation mapped within the hutH gene and in merodiploid strains was dominant over the wild-type allele. Extracts from cells bearing the trans-dominant histidase-negative allele were shown to contain material that reacts immunologically with antiserum against purified wild-type histidase. It is proposed that the trans-dominant allele results in the synthesis of defective histidase subunits that can combine with, and partially inactivate, wild-type histidase subunits. This subunit mixing presumably does occur, as the enzyme synthesized in a hybrid merodiploid strain is abnormally heat sensitive.

¹ Present address: Department of Biochemistry, Stanford University, Stanford, Calif. 94305