This study aimed to investigate the variations in the protein composition of Streptomyces sp. PU10 when cultivated with either Impranil (polyestere-polyurethane) or glucose as the carbon source. We analyzed both the intracellular and extracellular protein fractions to gain insights into the intricate processes involving PU degradation, intermediate metabolic pathways in PU degradation, and the connection between primary and secondary metabolism within Streptomyces sp. PU10.