[Regulation of the activity and synthesis of 3-deoxy-D-arabinoheptuloso-7-phosphate synthase in the obligate methylotroph Methylobacillus flagellatum KT].
The activity of the first enzyme of aromatic path 3-deoxy-D-arabino-heptuloso-7-phosphate-synthase (DAHP-synthase) is regulated by retro-inhibition and is a subject of repression. Analysis of partially purified preparations of the enzyme has revealed three isoenzymes: DAHP-synthase-Tyr, DAHP-synthase-Trp and DAHP-synthase-Phe, each of them being regulated by a corresponding amino acid. DAHP-synthase-Phe is a dominant isoenzyme presenting 70% of the enzyme activity, 30% inhibition of which is possible by 7.0 mkM of phenylalanine. DAHP-synthase-Tyr and DAHP-synthase-Trp are minor isoenzymes (sharing 15% of enzyme activity each) and are controlled by tyrosine and tryptophane correspondingly. 50% of inhibition of activity is possible by adding 0.7 and 0.8 mkM of corresponding amino acid. Regulation of the enzyme synthesis was studied in the Trp-, Phe- and Tyr- mutants. The enzyme activity was registered under the conditions of limiting and surplus of each aromatic amino acid. The synthesis of DAHP-synthase in M. flagellatum KT is repressed by tryptophane and tyrosine decreasing the synthesis 18.8 and 15.6 fold.
N P
NP
Maksimova
Iu K
IuK
Fomichev
D010723:3-Deoxy-7-Phosphoheptulonate Synthase / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D000596:Amino Acids / Q000494:pharmacology; D002848:Chromatography, DEAE-Cellulose; D019605:Euryarchaeota / Q000201:enzymology*; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D000432:Methanol / Q000378:metabolism; D009154:Mutation
D000596:Amino Acids; D007527:Isoenzymes; D010723:3-Deoxy-7-Phosphoheptulonate Synthase; D000432:Methanol
Reguliatsiia aktivnosti i sinteza 3-dezoksi-D-arabinogeptulozo-7-fosfatsintazy u obligatnogo metilotrofa Methylobacillus fagellatum KT.