Transcription of the gene for phosphoribosyl-anthranilate isomerase (TRP1) from the TRP1 promoter is initiated only approximately half as frequently as, for example, from the TRP3 promoter, but TRP1 mRNA is approximately twice as stable as TRP3 mRNA. Therefore, the steady state amount of TRP1 mRNA in yeast cells, grown without amino acid limitation, is similar to the steady-state amount of TRP3 mRNA. The protein concentration of both enzymes in yeast cells is about the same, but the basal specific enzyme activity in permeabilized cells of the TRP1 gene product N-(5'-phosphoribosyl-1)-anthranilate isomerase is about 2-3 times higher than that of any of the other TRP enzymes. According to the kinetic parameters of the purified isomerase protein, the enzyme is more active than, for example, the purified TRP3 enzyme indoleglycerol-phosphate synthase. It is suggested that the TRP1 gene of Saccharomyces cerevisiae might be the result of a rearrangement event, separating the N-(5'-phosphoribosyl-1)-anthranilate isomerase domain from the indoleglycerol-phosphate synthase domain and putting the catalytically more active isomerase domain behind a weak and nonregulated constitutive promoter.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Reference||Annotation Extension|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Conditions||Strain||Source||Reference|