THE BIOSYNTHESIS OF SOME AMINO ACIDS IN PENICILLIUM DIGITATUM
The pathways of biosynthesis of alanine, serine, glycine, aspartic acid, and glutamic acid in Penicillium digitntum have been studied by means of tracer techniques, using glucose-2-C14 and glucose-6-C11 as carbon sources. Alanine appears to be derived directly from pyruvate formed in the glycolytic degradation of glucose. Serine is synthesized from glycine, which is in turn derived mainly from a C2 fragment that originates in the C2–C3 cleavage of pentose, a product of phosphogluconate decarboxylation. The biosynthesis of aspartic acid in this organism may involve several pathways. Glutamic acid appears to be synthesized from glucose intermediates via the conventional reactions of the TCA cycle.