Structure and properties of major largomycin FII chromophore components.

Abstract

Largomycin FII [from Streptomyces pluricolorescens], a protein antitumor antibiotic of MW 29,300 daltons, contains a chromophore that is separable under mild denaturing conditions. The chromophore complex was considerably less stable than the holoprotein towards light and heat, suggesting a protective effect of the chromophore. Separation of the chromophore into several components was achieved using high performance liquid chromatography, and the biological activity of the isolated components was determined. Data gathered from UV, IR, proton and carbon NMR, and fast atom bombardment mass spectrometry indicated that all the chromophore components belong to the pluramycin class of antitumor agents. Pluramycin A and deacetylpluramycin A were the 2 major components.