H. Jahansouz, Devin M. Scherübel, R. Himes
Mar 26, 1990
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Influential Citations
3
Citations
Journal
FEBS Letters
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°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‐form‐ylTHF, 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.