Wild-type isopropylmalate isomerase in Salmonella typhimurium is composed of two different subunits.
AUTOR(ES)
Fultz, P N
RESUMO
The isopropylmalate isomerase in Salmonella typhimurium is the second enzyme specific for leucine biosynthesis. It is a complex enzyme composed of two subunits which are coded for by two genes of the leucine operon, leuC and leuD. The two polypeptides have been shown to copurify through successive ammonium sulfate fractionations and have been identified on sodium dodecyl sulfate-polyacrylamide gels as having molecular weights of 51,000 (leuC gene product) and 23,500 (leuD gene product). They have also been shown to be fairly stable, since in vitro complementation of cell-free extracts of leuC and leuD mutant strains was demonstrated, with only a 40% loss of activity 16 h after preparation of the extracts. The native isopropylmalate isomerase was shown to have a Km for its substrate alpha-isopropylmalate of 3 x 10(-4)M.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=216183Documentos Relacionados
- Quaternary constraint in hybrid of aspartate transcarbamylase containing wild-type and mutant catalytic subunits.
- Wild-type and mutant in vitro products of an operon for ribonucleic acid polymerase subunits.
- Utilization of D-xylose by wild-type strains of Salmonella typhimurium.
- Role of Endogenous Interleukin-18 in Resolving Wild-Type and Attenuated Salmonella typhimurium Infections
- Intracellular survival of wild-type Salmonella typhimurium and macrophage-sensitive mutants in diverse populations of macrophages.