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18 Oxygen incorporation into inorganic phosphate in the reaction catalyzed by N 5,10 ‐methenyltetrahydrofolate synthetase
Author(s) -
K. Kounga,
David G. Vander Velde,
Richard H. Himes
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)00396-q
Subject(s) - chemistry , catalysis , oxygen , phosphate , single displacement reaction , reaction mechanism , nitrogen , oxygen atom , nuclear chemistry , inorganic chemistry , organic chemistry , molecule
The mechanism of the N 5,10 ‐methenyltetrahydrofolate synthetase reaction was probed by determining the source of the oxygen atom introduced between the β‐ and γ‐phosphates as ATP is converted to ADP and P i . The reaction was performed using a mixture of [ 18 O]‐ and[ 16 O] N 5 ‐formyltetrahydrofolate in in the presence of [ 16 O]H 2 O and using[ 16 O] N 5 ‐formyltetrahydrofolate in the presence of a1:1 mixture of [ 18 O]H 2 O and [ 16 O]H 2 O. 31 P NMR spectroscopy was used to examine the products. It was found that 18 O from the formyl group was incorporated into P i , and that 18 O was not incorporated from the solvent. The results are consistent with a mechanism involving phosphorylation of the formyl group at the N 5 ‐position, followed by displacement of the phosphate by the 10‐nitrogen.