Application of capillary enzyme micro-reactor in enzyme activity and inhibitors studies of glucose-6-phosphate dehydrogenase

•CE-based G6PDH-IMERs were fabricated using the electrostatic assembly via PDDA layer.•IMERs exhibit good stability and reproducibility for on line enzyme assay of G6PDH.•G6PDH enzyme activity were measured on-line using the CE-based IMERs.•Inhibition constants and kinetics of six inhibitors were obtained by on-line CE assay.

In this study, we present an on-line measurement of enzyme activity and inhibition of Glucose-6-phosphate dehydrogenase (G6PDH) enzyme using capillary electrophoresis based immobilized enzyme micro-reactor (CE-based IMER). The IMER was prepared using a two-step protocol based on electrostatic assembly. The micro-reactor exhibited good stability and reproducibility for on-line assay of G6PDH enzyme. Both the activity as well as the inhibition of the G6PDH enzyme by six inhibitors, including three metals (Cu2+, Pb2+, Cd2+), vancomycin, urea and KMnO4, were investigated using on-line assay of the CE-based IMERs. The enzyme activity and inhibition kinetic constants were measured using the IMERs which were found to be consistent with those using traditional off-line enzyme assays. The kinetic mechanism of each inhibitor was also determined. The present study demonstrates the feasibility of using CE-based IMERs for rapid and efficient on-line assay of G6PDH, an important enzyme in the pentosephosphate pathway of human metabolism.