Involved in the biosynthesis of the anthracyclines carminomycin and daunorubicin (daunomycin) which are aromatic polyketide antibiotics that exhibit high cytotoxicity and are widely applied in the chemotherapy of a variety of cancers. Catalyzes the removal of methyl group from the carbomethoxy group of rhodomycin D (10-carbomethoxy-13-deoxycarminomycin) and 4-O-methylrhodomycin D to yield 10-carboxy-13-deoxycarminomycin and 10-carboxy-13-deoxydaunorubicin, respectively. Could be also involved in the decarboxylation of 10-carboxy-13-deoxycarminomycin and 10-carboxy-13-deoxydaunorubicin to yield 13-deoxycarminomycin and 13-deoxydaunorubicin, respectively. It seems that DnrK may influence the ability of DnrP to carry out the decarboxylation (Probable). H2O + rhodomycin D = 10-carboxy-13-deoxycarminomycin + H(+) + methanol 4-O-methylrhodomycin D + H2O = 10-carboxy-13-deoxydaunorubicin + H(+) + methanol Antibiotic biosynthesis; daunorubicin biosynthesis. Antibiotic biosynthesis; carminomycin biosynthesis. Belongs to the methyl esterase DnrP family.