NOVEL ANTIBIOTIC RK-441, PRODUCTION THEREOF, ANTITUMOR AGENT AND IMMUNOSUPPRESSIVE AGENT

摘要

NEW MATERIAL:An antibiotic substance RK-441 expressed by the formula. USE:An antitumor agent and immunosuppressive agent. PREPARATION:A microorganism [e.g. Streptomyces espi RK-441 (FERM P-10306)] belonging to the genus Streptomyces having producing ability of antibiotic substance RK-441 is inoculated into culture medium and cultured by a method such as submerged culture to provide the antibiotic substance RK-441 expressed by the formula. Nutrition source of the culture medium is not especially limited and can contain ordinary carbon source (e.g. starch, dextrin or glycerin), nitrogen source (e.g. peptone, soybean powder, etc.). The pH of the culture medium is preferably 4-9, especially preferably nearly neutral and temperature thereof is preferably about 25-35 deg.C.