title: The role of formylmethanofuran: tetrahydromethanopterin formyltransferase in methanogenesis from carbon dioxide.
abstract: Formylmethanofuran: tetrahydromethanopterin formyltransferase was purified to electrophoretic homogeneity from cells of Methanobacterium thermoautotrophicum. The enzyme is a tetramer of similar or identical subunits (Mr = 41,000). The equilibrium favors transfer of the formyl group to tetrahydromethanopterin (H4MPT) at physiological pH. The product of formyl transfer by the purified enzyme was shown by a number of criteria to be 5-formyl-H4MPT, as opposed to 10-formyl-H4MPT or 5,10-methenyl-H4MPT. Reconstitution of a portion of the methanogenic C1 cycle was effected by combining purified formyltransferase, methenyl-H4MPT cyclohydrolase, formylmethanofuran, and H4MPT to give methenyl-H4MPT. Additional reconstitution experiments established that the formyltransferase is an essential enzyme for the conversion of carbon dioxide to methane. In conjunction with previously published data (Donnelly, M.I., Escalante-Semerena, J.C., Rinehart, K. L., Jr., and Wolfe, R.S. (1985) Arch. Biochem. Biophys. 242, 430-439), these data substantiate the role of 5-formyl-H4MPT as an intermediate of methanogenesis.
mesh_terms: D002245:Carbon Dioxide / Q000378:metabolism*; D019605:Euryarchaeota / Q000201:enzymology*; D005663:Furans / Q000378:metabolism*; D019877:Hydroxymethyl and Formyl Transferases; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D014166:Transferases / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D005663:Furans; D046911:Macromolecular Substances; D002245:Carbon Dioxide; C050842:formylmethanofuran; D014166:Transferases; D019877:Hydroxymethyl and Formyl Transferases; C050840:formylmethanofuran-tetrahydromethanopterin formyltransferase