DIRECTED BIOSYNTHESIS OF 5''-FLUOROPACTAMYCIN IN STREPTOMYCES-PACTUM

A new pactamycin analogue, 5''-fluoropactamycin, was prepared by direc ted biosynthesis. Supplementation of the fermentation medium of Strept omyces pactum, var. pactum with 3-amino-5-fluorobenzoic acid, an analo gue of 3-aminobenzoic acid, an advanced precursor in pactamycin biosyn thesis, resulted in co-production of pactamycin and the new pactamycin analogue. A similar feeding experiment with 3-amino-5-methylbenzoic a cid did not result in formation of the corresponding methylated pactam ycin analogue, but only in inhibition of pactamycin production. Compar ison of antimicrobial and cytotoxic activities of pactamycin and 5''-f luoropactamycin showed no significant differences.