Catabolite repression of the lac operon. The contribution of transcriptional repression
نویسندگان
چکیده
منابع مشابه
Catabolite repression of the lac operon. Separt epressionof two enzymes.
1. Catabolite repression of beta-galactosidase and of thiogalactoside transacetylase was studied in several strains of Escherichia coli K 12, in an attempt to show whether a single site within the structural genes of the lac operon co-ordinately controls translational repression for the two enzymes. In all experiments the rate of synthesis of the enzymes was compared in glycerol-minimal medium ...
متن کاملCatabolite repression of the lac operon. Effect of mutations in the lac promoter.
1. Several lac diploid strains of Escherichia coli were constructed and tested to discover whether mutations in the lac promoter alleviate catabolite repression. 2. In each of these diploids the chromosome carries one of the promoter mutations, L8, L29 or L1; so that the rate of synthesis of the enzymes of the lac operon is only 2-6% of the fully induced wild-type. Each diploid harbours the epi...
متن کاملTransient repression of the lac operon.
Severe transient repression of constitutive or induced beta-galactosidase synthesis occurs upon the addition of glucose to cells of Escherichia coli growing on glycerol, succinic acid, or lactic acid. Only mutants particularily well adapted to growth on glucose exhibit this phenomenon when transferred to a glucose-containing medium. No change in ribonucleic acid (RNA) metabolism was observed du...
متن کاملInfluence of catabolite repression and inducer exclusion on the bistable behavior of the lac operon.
A mathematical model of the lac operon which includes all of the known regulatory mechanisms, including external-glucose-dependent catabolite repression and inducer exclusion, as well as the time delays inherent to transcription and translation, is presented. With this model we investigate the influence of external glucose, by means of catabolite repression and the regulation of lactose uptake,...
متن کاملThe three operators of the lac operon cooperate in repression.
We tested the effect of systematic destruction of all three lac operators of the chromosomal lac operon of Escherichia coli on repression by Lac repressor. Absence of just one 'pseudo-operator' O2 or O3 decreases repression by wild-type tetrameric Lac repressor approximately 2- to 3-fold; absence of both 'pseudo-operators' decreases repression greater than 50-fold. O1 alone represses under thes...
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ژورنال
عنوان ژورنال: Biochemical Journal
سال: 1969
ISSN: 0306-3283
DOI: 10.1042/bj1140307