Regulative influence of o-aminobenzoic acid on the biosynthesis of nourseothricin in cultures of Streptomyces noursei JA 3890b. III. Change of redox state of nicotinamide-adenine-dinucleotides in the presence of aminobenzoic acids.

o-Aminobenzoic acid (OABA, anthranilic acid) and related compounds which are known to stimulate the biosynthesis of streptothricin-type antibiotic nourseothricin by Streptomyces noursei JA 3890b were found to increase strongly the NADH/NAD+ ratio in growing mycelium of this strain suggesting that these effectors are capable of interfering with the function of the respiratory chain. In parallel, a complex shift of metabolism was induced shown by simultaneous alteration of mycelial activities of alanine dehydrogenase, glutamine synthetase, and glutamate dehydrogenase. These changes may be responsible for the observed delay of amino acid catabolism and may improve the precursor supply of the secondary metabolism.