title: 5-Formyl-5,6,7,8-tetrahydromethanopterin is the intermediate in the process of methanogenesis in Methanosarcina barkeri.
abstract: Formylmethanofuran:tetrahydromethanopterin (H4MPT) formyltransferase and 5,10-methenyl-H4MPT cyclohydrolase purified from Methanosarcina barkeri catalyze a formyl group transfer and the hydrolysis of the methenyl function, respectively. The results from UV spectroscopy and HPLC analyses, and comparison with results obtained with the enzymes isolated from Methanobacterium thermoautotrophicum showed 5-formyl-H4MPT to be the product of the formyltransferase and cyclohydrolase reactions in M. barkeri. The findings disagree with an earlier report in which 10-formyl-H4MPT was identified as the product of the cyclohydrolase in the latter organism. In addition, it was observed that 10-formyl-H4MPT, which is non-enzymically formed from 5,10-methenyl-H4MPT at alkaline pH, becomes rapidly converted into the 5-formyl derivative. The latter finding explains why the nature of the formyl species previously had been improperly assigned.
authors.affiliation: Department of Microbiology, Faculty of Science, University of Nijmegen, The Netherlands.
authors.forename: J T
authors.initials: JT
authors.lastname: Keltjens
authors.forename: A J
authors.initials: AJ
authors.lastname: Brugman
authors.forename: J M
authors.initials: JM
authors.lastname: Kesseleer
authors.forename: B W
authors.initials: BW
authors.lastname: te Brömmelstroet
authors.forename: C
authors.initials: C
authors.lastname: van der Drift
authors.forename: G D
authors.initials: GD
authors.lastname: Vogels
mesh_terms: D000619:Aminohydrolases / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D019877:Hydroxymethyl and Formyl Transferases; D008697:Methane / Q000378:metabolism*; D017020:Methanosarcina / Q000201:enzymology; D017021:Methanosarcina barkeri / Q000201:enzymology / Q000378:metabolism*; D015394:Molecular Structure; D011622:Pterins / Q000378:metabolism*; D014166:Transferases / Q000032:analysis
chemical_list: D011622:Pterins; C054050:5-formyl-5,6,7,8-tetrahydromethanopterin; D014166:Transferases; D019877:Hydroxymethyl and Formyl Transferases; C050840:formylmethanofuran-tetrahydromethanopterin formyltransferase; D000619:Aminohydrolases; C050675:methenyltetrahydromethanopterin cyclohydrolase; D008697:Methane