NEW MATERIAL:An antibacterial substance having the following physical and chemical properties. Elemental analysis (%), C 58.3, H 6.1, N 2.3, O 33.5; molecular formula, C29H37NO11 (molecular weight: 574); melting point, 106W112°C; ultraviolet absorption spectrum (in water), λmax(E11cm)=215(333), 254(137), 435(35.5); specific rotation, [α]22.5D=-50.0° (C=0.098, H2O); color reaction, positive to magnesium acetate, nitroprusside-acetaldehyde and Dragendorff, negative to ninhydrin and Elson-Morgan; solubility, soluble in water, methanol and ethanol, insoluble in acetone, ethyl acetate, chloroform, etc.; appearance crystalline powder; nature, basic.

USE: Antitumor agent.

PREPARATION: A tokimycin-producing microbial strain belonging to Strepto- myces genus (FERM P-8321) is cultured aerobically in a medium containing nutrient source.