REPRESSION-DEPENDENT ALTERATION OF AN ARGININE ENZYME IN Escherichia coli
AUTOR(ES)
Leisinger, Thomas
RESUMO
Treatment of susceptible Escherichia coli K12 derivatives with 0.4 M Mg++ at 37°, potentiated by L-arginine or L-canavanine, leads to alteration of acetylornithine δ-transaminase. The alteration, obtained in the absence of protein synthesis and reversible at 0 or 37°, is manifested in extracts by lowered activity and modified substrate affinity behavior of the enzyme without gross changes in sedimentation properties. Cells grown under arginine repression are susceptible to the treatment; cells grown under genetic or steady-state physiological derepression are not. Transaminase synthesized during early derepression can be altered, although to progressively diminishing extents. Enzyme formed under steady-state derepression becomes alterable following transition to repression. The Mg++ -dependent alteration can be thought to arise while the enzyme, arginine (or canavanine), and aporepressor are in contact, and to reflect a physiological process such as the participation of the enzyme in the repressive complex.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=223399Documentos Relacionados
- Repression of Escherichia coli carbamoylphosphate synthase: relationships with enzyme synthesis in the arginine and pyrimidine pathways.
- Translational Repression in the Arginine System of Escherichia coli*
- Accumulation of arginine precursors in Escherichia coli: effects on growth, enzyme repression, and application to the forward selection of arginine auxotrophs.
- Control of Arginine Biosynthesis in Escherichia coli: Role of Arginyl-Transfer Ribonucleic Acid Synthetase in Repression
- Roles of Arginine and Canavanine in the Synthesis and Repression of Ornithine Transcarbamylase by Escherichia coli