Anaerobic O-demethylations of methoxynaphthols, methoxyfuran, and fluoroanisols by Sporomusa ovata.

In vitro experiments with 3,4-dimethoxybenzoate-induced Sporomusa enzymes a broad O-methyl ether cleavage capacity. The O-demethylase activity hydrolized the methyl-oxygen linkages of methoxynaphtholes of the heterocycles 2-methoxyfuran or 2-methoxythiophene as well as of several dimethoxy and monomethoxy aryls under anaerobic conditions. Also, fluoro and chloro substituents of anisoles enhanced the O-demethylation rate, indicating that an electron delocalized aromatic structure supported the methyl ether activation mechanism. Monomethoxy aromatics with additional chargeable groups, however, were less effectively transformed by the O-demethylase activity. No transformations into hydroxylated products occurred with 4-(trifluoromethoxy)benzyl alcohol, 4-(trifluoromethoxy)fluorobenzene, 2,5-dimethoxytetrahydrofuran, or alkyl-O-methyl ethers. The inert ethers did not affect the 3,4-dimethoxybenzoate metabolism. Ether activation or the following methyl transfer to the methyl acceptor tetrahydrofolate involved a prominent 31 kDa peptide from the cytoplasmic cell fraction, because this particular peptide was lacking in cells grown with methanol, betaine or fructose.