NMR studies on mechanism of isomerisation of fructose 6-phosphate to glucose 6-phosphate catalysed by phosphoglucose isomerase from Thermococcus kodakarensis

Abstract The fate of hydrogen atoms at C-2 of glucose 6-phosphate (G6P) and C-1 of fructose 6-phosphate (F6P) was studied in the reaction catalysed by phosphoglucose isomerase from Thermococcus kodakarensis ( Tk PGI) through 1D and 2D NMR methods. When the reaction was performed in 2 H 2 O the hydrogen atoms in the aforementioned positions were exchanged with deuterons indicating that the isomerization occurred by a cis -enediol intermediate involving C-1 pro-R hydrogen of F6P. These features are similar to those described for phosphoglucose isomerases from rabbit muscle and Pyrococcus furiosus .