FIGURE 6.

Confirmation of the product of the reaction catalyzed by human FGGY as ribulose 5-phosphate. A, a reaction mixture resulting from the PK/LDH coupled d-ribulokinase assay was analyzed using ZIC-HILIC-ddMS2. The extracted ion chromatogram (m/z 229.0108, negative ionization mode) shows a peak at retention time 7.92 min that co-elutes with the external analytical standard d-ribulose 5-phosphate. B, head-to-tail comparison of the MS2 fragmentation pattern of the parent ion m/z 229.0108 eluting at 7.92 min during analysis of the enzyme assay mixture and of the co-eluting ion from the external d-ribulose 5-phosphate standard.