ANAEROBIC O-DEMETHYLATIONS OF METHOXYNAPHTHOLS, METHOXYFURAN, AND FLUOROANISOLS BY SPOROMUSA-OVATA

In vitro experiments with 3,4-dimethoxybenzoate-induced Sporomusa enzy mes evaluated a broad O-methyl ether cleavage capacity. The O-demethyl ase activity hydrolized the methyl-oxygen linkages of methoxynapht-hol es of the heterocycles 2-methoxyfuran of 2-methoxythiophene as well as of several dimethoxy and mono-methoxy aryls under anaerobic condition s. Also, fluoro and chloro substituents of anisoles enhanced the O-dem ethylation rate, indicating that an electron delocalized aromatic stru cture supported the methyl ether activation mechanism. Monomethoxy aro matics with additional chargeable groups, however, were less effective ly transformed by the O-demethylase activity. No transformation into h ydroxylated products occurred with 4-(trifluoromethoxy)benzyl alcohol, 4-(trifluoromethoxy)fluorobenzene, 2,5-dimethoxytetrahydrofuran, or a lkyl-O-methyl ethers. The inert ethers did not affect the 3,4-dimethox ybenzoate metabolism. Ether activation or the following methyl transfe r to the methyl acceptor tetrahydrofolate involved a prominent 31 kDa peptide from the cytoplasmic cell fraction, because this particular pe ptide was lacking in cells grown with methanol, betaine or fructose. ( C) 1996 Academic Press, Inc.