Kitamycins, New Antimycin Antibiotics Produced by Streptomyces sp.

In the course of our screening program for plant growth inhibitors, Streptomyces sp.K385 isolated from a soil sample collected in OkayamaJapan, was found to produce kitamycin A (1) and B (2), new antimycin type antibiotics, together with known antimycin type antibiotics, antimycin A1? A2a, A3, A4a1?2), urauchimycin B (3)3), and deisovalerylblastmycin (4).4?5)This study describes the fermentation, isolation, structure elucidation and biological activity of 1 and 2 and stereochemistry of 3. The strain K385 was cultivated in the medium consisting of dextrin 1.5%, soybean meal 0.4%, peptone 0.1%, meat extract 0.1%, yeast extract 0.1% and corn steep liquor 0.1% (pH 7.2) for 2 days at 28°C.This seed