Regulation of 3-Deoxy-D-arabinoheptulosonate-7-phosphate (DAHP) Synthase of Bacillus sp. B-6 Producing Phenazine-1-carboxylic acid

摘要

The 3-Deoxy-D-arabinoheptulosonate 7-phosphate (DAHP) synthase is the first enzyme of aromatic amino acid-, folic acid-, and phenazine-1-carboxylic acid biosynthetic pathways. DAHP synthase of Bacillus sp. B-6 that produces phenazine-1-carboxylic acid was feedback inhibited by two intermediary metabolites of aromatic amino acid biosynthetic pathways, prephenate and chorismate, but not by other metabolites, such as anthranilic acid, shikimic acid, p-aminobenzoic acid, and 3-hydroxyanthranilic acid. DAHP synthase of Bacillus sp. B-6 was not inhibited by end products such as aromatic amino acids, folic acid, and phenazine- 1-carboxylic acid. The inhibition of DAHP synthase by prephenate and chorismate was non competitive with respect to erythrose 4-phosphate and phosphoenolpyruvate. Prephenate and chorismate inhibited 50% of the DAHP synthase activity at concentrations of 2 * 10~(-5) M and 1.2 * 10~(-4) M, respectively. The synthesis of DAHP synthase of Bacillus sp. B-6 was not repressed by exogenous aromatic amino acids, folic acid, and phenazine 1-carboxylic acid, single or in combinations.