1-(o-Carboxyphenylamino)-1-deoxyribulose. A compound formed by mutant strains of Aerobacter aerogenes and Escherichia coli blocked in the biosynthesis of tryptophan

Abstract

A new compound was found to be accumulated by washed cell suspensions of mutant strains of Aerobacter aerogenes (N 3-33, N 2-18) and Escherichia coli (R 19-33) requiring tryptophan or indole for growth. This compound has been identified as l-(o-carboxyphenylamino)-l-deoxyribulose and may be the immediate precursor of indolylglycerol phosphate in tryptophan synthesis. Color reactions of the natural compound (Y), isolated on paper chromatograms, indicated the presence of a sugar fragment, probably a pentulose. Reducing properties suggested an Amadori compound. A number of glycosylamines of anthranilic acid were synthesized and used as model compounds for UV-absorption spectrophotometry and as parent compounds in Amadori-rearrangement reactions. The spectral and other characteristics of the products were determined with material from paper chromatograms. A comparison of the properties of the synthetic compounds with those of compound Y indicated that the latter was identical with l-(o-carboxyphenylamino)-l-deoxyribulose. The differentiation from l-(o-carboxyphenylamino)-l-deoxy-D-fructose was on the basis of color reaction, Rf and stability at alkaline pH. A xylulose structure was rejected on grounds of Rf. The preparation of an identical 2:4-dinitrophenylhydrazone derivative from compound Y and from synthetic l-(o-carboxyphenylamino)-l-deoxyribulose confirmed the pentose Amadori structure and the identity of compound Y.