Formylation of tetrahydrofolate by formyl phosphate.
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.
Jahansouz
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H
Department of Biochemistry, University of Kansas, Lawrence 66045-2106.
Scherübel
D M
DM
Himes
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RH
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
D009943:Organophosphorus Compounds; D013763:Tetrahydrofolates; C053858:formyl phosphate; D009584:Nitrogen