title: Formylation of tetrahydrofolate by formyl phosphate.
abstract: Formyl phosphate is the putative intermediate in the formylation of tetrahydrofolate (THF) catalyzed by N10-formylTHF synthetase. In this study the non-enzymic reaction between formyl phosphate and THF was examined at 5 degrees C. 1H-NMR, HPLC and kinetic analysis of the proton-catalyzed conversion of the product to N5,10-methenylTHF were used to identify the product. In contrast to the enzyme reaction, which produces N10-formylTHF, N5-formylTHF was the only formylated THF derivative formed. The reaction was conducted at pH values of 3, 5, and 7, with the highest yield being obtained at pH 5 (64-85%, based on THF). The enzyme, therefore, changes the regioselectivity of this reaction by increasing the reactivity of the 10-nitrogen and either decreasing the reactivity of the 5-nitrogen or limiting its accessibility to formyl phosphate. 2-Mercaptoethanol, present in the reaction mixture to protect THF from O2, was also formylated by formyl phosphate, at the oxygen position.
authors.affiliation: Department of Biochemistry, University of Kansas, Lawrence 66045-2106.
authors.forename: H
authors.initials: H
authors.lastname: Jahansouz
authors.forename: D M
authors.initials: DM
authors.lastname: Scherübel
authors.forename: R H
authors.initials: RH
authors.lastname: Himes
mesh_terms: D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D009584:Nitrogen; D009943:Organophosphorus Compounds; D013763:Tetrahydrofolates
chemical_list: D009943:Organophosphorus Compounds; D013763:Tetrahydrofolates; C053858:formyl phosphate; D009584:Nitrogen