DMI-1, A NEW DNA METHYLTRANSFERASE INHIBITOR PRODUCED BY STREPTOMYCESSP STRAIN NO-560

A new inhibitor of DNA methyltransferase named DMI-1 has been discover ed in the culture filtrate of Streptomyces sp. strain No. 560. DMI-1 w as purified by extraction with ethyl acetate followed by Diaion HP-20S S and silica,eel column chromatography. The structure of DMI-1 was det ermined to be 8-methylpentadecanoic acid (C16H32O2). DMI-1 is a novel inhibitor of methyltransferase isolated from microorganisms and is str ucturally different from sinefungin and A9145C which are structural an alogs of S-adenosylmethionine (methyl donor). DMI-1 was a strong inhib itor of N-6-methyladenine-DNA methyltransferase (M. Eco RI, EC 2.1.1.7 2) in a noncompetitive manner and its inhibition depended on the pH an d temperature in the assay media.