Studies in the biochemistry of micro-organisms. 116. Biosynthesis of β-nitropropionic acid by the mould Penicillium atrovenetum G. Smith

Abstract

[l-14C]Acetate and[2-14C]pyruvate were used for studying the production of [beta]-nitropropionic acid by P. atro-venetum, and a method of degrading the nitro acid so that each Ca could be obtained separately was developed. The radioactivity incorporated into [beta]-nitropropionic acid indicated that these compounds were incorporated by the tricarboxylic acid cycle into oxaloacetate and the [beta]-nitropropionic acid Ca skeleton was derived from this by loss of C-4. Aspartic acid was isolated from the mycelium used for [beta]-nitropropionic acid production with [2-14C]pyruvate as tracer. The portionof the molecule remaining after subtraction of C-4 has a specific radioactivity almost identical with [beta]-nitropropionic acid and contains the same distribution of radioactivity. The unequal distribution of radioactivity in C-2 and C-3 of [2-^C]pyruvate-derived [beta]-nitroprpionic acid indicated that fumaric acid, could not be a direct precursor. The level of oxidation of N introduced into oxalacetate whether amino or more oxidized, e.g. hydroxylamine, and the possible relationship with hetero-trophic nitrification are discussed.