[Role of p-aminobenzoic acid in levorin biosynthesis].

: The effect of p-aminobenzoic acid on the biosynthesis of levorin was studied. It was shown that in the presence of exogenic p-aminobenzoic acid the antibiotic activity increased by 11 per cent. The acid added was transformed into p-aminoacetophenone which was partially used for levorin synthesis and partially accumulated in the mycelium in a free state. In this case the synthesis of levorin was limited by the metabolites forming the macrolide ring. When the precursors of the macrolide ring and the aromatic group were simultaneously added to the medium, the content of free p-aminoacetophenone in the mycelium decreased while the antibiotic activity increased by 25 per cent.