Sibiromycin (GMP) refers to the GMP grade reagents of Sibiromycin. Sibiromycin is a glycosylated pyrrolo-pyridinone (PBDs) compound, and it is a naturally occurring potent anti-tumor antibiotic. Its activity is exerted by forming covalent bonds with DNA at the groove of the guanine's amino terminus.

Pyrrolobenzodiazepines (PBDs) are sequence selective DNA alkylating agents with remarkable antineoplastic activity[1]. Alkylation of DNA by anthramycin, sibiromycin and tomaymycin is sequence specific with the following trend for binding preference 5′-Pu-G-Pu>5′-Py-G-Pu>5′-Pu-G-Py>5′-Py-G-Py[1]. Sibiromycin shows cytotoxicity against L1210 (leukemia), ADJ/PC6 (plasmacytoma) and CH1 (ovarian) cells with IC50s of ranging 0.000017 ~0.0029 μM[1].