Aminoacetone as the penultimate precursor to the antitumor agent azinomycin A.

Experiments reveal that the metabolic precursor aminoacetone is a key intermediate in the production of the antitumor agent azinomycin A relative to the structurally and functionally related agent, azinomycin B. Azinomycin A and B arise through bifurcation of the biosynthetic pathway and competition between metabolic substrates. The availability of the biosynthetic precursors in vivo, aminoacetone for azinomycin A and threonine for azinomycin B, controls the overall ratio of azinomycin A to B produced.