Inhibition of DNA Methyltransferase by Microbial Inhibitors and Fatty Acids

AbstractStrepromyces sp. strain No. 560 produces four kinds of DNA methyltransferase inhibitors in the culture filtrate. One of them, DMI-4 was distinguished from DMI-1, -2 and -3 previously reported with respect to certain properties. DMI-4 is considered to be a triglyceride consisting of the fatty acids anteisopentadecanoic acid (C15:0), isopalmitic acid (Cl6:0) and isostearic acid (C18:0) from the results of gas chromatography analysis. Since DMI-4 contains three molecules of fatty acid, and the previously reported DMI-1, 8-methylpentadecanoic acid, is analogous to a fatty acid, the inhibitory activity has been examined of various fatty acids and their methyl esters against Eco RI DNA methyltransferase (M. Eco RI).Oleic acid (C18:1) was found to be a potent inhibitor of M. Eco RI. The inhibitory activity of oleic acid was shown to be pH- and temperature-dependent and inhibited M. Eco RI in a noncompetitive manner with respect to DNA or S-adenosylmethionine (SAM).The number of carbon atoms and double bo...