[New antibiotic, cinropeptin, from a culture of Act. cineraceus].

Cinropeptin, a new antibacterial antibiotic, was isolated from the mycelium of a culture classified as belonging to Act. cineraceus. Its empirical formula is C50H63N11O12S6, [alpha]D--169.4 degrees (C 0.36, CHCl3). The UV absorption maxima of the antibiotic in an alcoholic solution were observed at 218, 232, 304 and 365 nm. The IR absorption bands were recorded at 3370, 1660, 1600, 1530, 1140 and 1100 cm-1. Cystin, glycine and methylamine were detected in the acid hydrolysate of cinropeptin. Study on the products of the antibiotic partial oxidation with performic acid and comparison of the sulfur percentage and molecular weight showed that the molecule of cinropeptin contained 3 residues of cystin.