In the previous paper,¹⁾ the substances produced by Streptomyces No. 732 and No. 1752 were described to be mixtures of three components and each component coincided with one another, although the ratios of content of components were different in the two strains.

The three components shall be named quinomycins A, B and C, respectively. In the present publication, the production of the quinomycins and the purification procedures of quinomycins A and C are described. Quinomycin A was isolated from Streptomyces No. 1752 and quinomycin C from Streptomyces No. 732. The physical, chemical and biological properties of the quinomycins are also described in comparison with those of echinomycin. Quinomycin A is identical with echinomycin²⁾ according to the paperchromatogram, but quinomycins B and C are considered to be new antibiotics.