A novel extracellular protein of Streptomyces peucetius binds to daunorubicin but does not inhibit the bioactivity of the antibiotic

Abstract

Extracellular proteins of Streptomyces peucetius that bind to a red pigment were identified during the course of isolation of mutants defective in daunorubicin production. Two pigment-protein complexes were partially purified and this complex inhibited the growth of Bacillus subtilis. Routine solvent extraction could not separate the pigment from purified pigment-protein complex. Treatment with 2% SDS at 100°C followed by solvent extraction also failed to separate the protein from the pigment. However, the pigment could be separated from the purified pigment-protein complex by heating it in 0.1 M HCl at 100 °C followed by solvent extraction. The pigment extracted from the complex was analyzed by HPLC and found to be daunorubicin.