Growth, enzyme levels, and some metabolic properties of an Escherichia coli mutant grown on L-threonine as the sole carbon source.
AUTOR(ES)
Boylan, S A
RESUMO
A mutant of Escherichia coli (designated E. coli SBD-76) that utilizes L-threonine as the sole carbon source was isolated. In contrast with levels in extracts of wild-type cells, the levels of threonine dehydrogenase in extracts of this mutant were 100-fold higher than levels of threonine aldolase or degradative threonine dehydratase. Catabolite repression of threonine dehydrogenase was manifested in wild-type, but not SBD-76, cells. For purposes of isolating enzymes, large quantities of SBD-76 cells with the elevated threonine dehydrogenase level could be grown in a fermentor in modified Fraser medium containing 1% glycerol, rather than in the 0.2% L-threonine minimal medium used to isolate the mutant. SBD-76 cells grown on L-threonine excreted glycine and aminoacetone into the medium, and extracts of the mutant strain catalyzed a quantitative conversion of L-threonine to glycine and aminoacetone.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=215080Documentos Relacionados
- Growth, Enzyme Levels, and Some Metabolic Properties of an Escherichia coli Mutant Grown on l-Threonine as the Sole Carbon Source
- THE METABOLISM OF L-THREONINE AND GLYCINE BY Escherichia coli*
- Production of l-Threonine by Auxotrophic Mutants of Escherichia coli
- Acetohydroxy acid synthase I, a required enzyme for isoleucine and valine biosynthesis in Escherichia coli K-12 during growth on acetate as the sole carbon source.
- THREONINE DEAMINATION IN ESCHERICHIA COLI II. : Evidence for Two l-Threonine Deaminases1