Biomaterial Database

Unstable mutations that relieve catabolite repression of tryptophanase synthesis by Escherichia coli. 1977

M D Yudkin

From strains of Escherichia coli that carry deletions of the trp region, five different mutants were isolated that were capable of synthesizing tryptophanase at unusually high rates in conditions of severe catabolite repression. Notwithstanding the comparative insensitivity to catabolite repression, the rates of tryptophanase synthesis in the mutants were greatly diminished by the introduction of a defective gene for adenyl cyclase. Each of the mutants segregated variants of the parental type. The results of genetic analysis appear to be consistent with the mutants arose by duplication of the tryptophanase gene.

UI	MeSH Term	Description	Entries
D008190	Lyases	A class of enzymes that catalyze the cleavage of C-C, C-O, and C-N, and other bonds by other means than by hydrolysis or oxidation. (Enzyme Nomenclature, 1992) EC 4.	Desmolase,Desmolases,Lyase
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D004794	Enzyme Repression	The interference in synthesis of an enzyme due to the elevated level of an effector substance, usually a metabolite, whose presence would cause depression of the gene responsible for enzyme synthesis.	Repression, Enzyme
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005796	Genes	A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.	Cistron,Gene,Genetic Materials,Cistrons,Genetic Material,Material, Genetic,Materials, Genetic
D000262	Adenylyl Cyclases	Enzymes of the lyase class that catalyze the formation of CYCLIC AMP and pyrophosphate from ATP.	Adenyl Cyclase,Adenylate Cyclase,3',5'-cyclic AMP Synthetase,Adenylyl Cyclase,3',5' cyclic AMP Synthetase,AMP Synthetase, 3',5'-cyclic,Cyclase, Adenyl,Cyclase, Adenylate,Cyclase, Adenylyl,Cyclases, Adenylyl,Synthetase, 3',5'-cyclic AMP
D014161	Transduction, Genetic	The transfer of bacterial DNA by phages from an infected bacterium to another bacterium. This also refers to the transfer of genes into eukaryotic cells by viruses. This naturally occurring process is routinely employed as a GENE TRANSFER TECHNIQUE.	Genetic Transduction,Genetic Transductions,Transductions, Genetic
D014368	Tryptophanase	An enzyme that catalyzes the conversion of L-tryptophan and water to indole, pyruvate, and ammonia. It is a pyridoxal-phosphate protein, requiring K+. It also catalyzes 2,3-elimination and beta-replacement reactions of some indole-substituted tryptophan analogs of L-cysteine, L-serine, and other 3-substituted amino acids. (From Enzyme Nomenclature, 1992) EC 4.1.99.1.	Tryptophan Indole-Lyase,Indole-Lyase, Tryptophan,Tryptophan Indole Lyase
D014644	Genetic Variation	Genotypic differences observed among individuals in a population.	Genetic Diversity,Variation, Genetic,Diversity, Genetic,Diversities, Genetic,Genetic Diversities,Genetic Variations,Variations, Genetic