INFLUENCE OF 3-METHYLANTHRANILIC AND ANTHRANILIC ACIDS ON THE FORMATION OF TRYPTOPHAN SYNTHETASE INESCHERICHIA COLI

Publisher Website
Google Scholar
Abstract
Of several analogues of anthranilic acid only the addition of 3-methylanthranilic acid (3-MA) to the growth medium stimulated the formation of tryptophan synthetase. This effect of 3-MA was not directly on the enzyme forming system, but was traced to an inhibition of the formation of tryptophan, which represses the formation of tryptophan synthetase. The site of action of 3-MA was the conversion of anthranilic ribo-nucleotide to indole-3-glycerol phosphate, as evidenced by the accumulation of the former compound in cultures grown in the presence of 3-MA. Anthranilic acid, a precursor of tryptophan, also inhibited the same reaction, and the resulting limitation of tryptophan synthesis led to increased levels of tryptophan synthetase. Thus, an intermediate was observed to inhibit a subsequent reaction in a biosynthetic sequence; the implications of these observations are discussed.