Fig. 7.

Catalytic activity of WT, S263P and G264S enzymes in HEK293 cell extracts. (A): Glucose-dependent GK activity in cytosolic fractions of stably transfected HEK293 cells, prepared by mechanical shear forces. The activity was measured spectrophotometrically at 30 °C at equal amounts of cellular GK (~100 μg of total protein), as determined by SDS/PAGE (10 %) and immunoblotting (anti-GK and anti-actin Ab) (B). (C): Kinetic parameters calculated from data in (A) by nonlinear regression analysis using the Hill equation. Data represents the mean ± SD of three independent experiments (n = 3).