Investigation of the in Vitro Effects of Graphene Oxide on the Xanthine Oxidase Activity

Graphene is a two-dimensional structure which consists of carbon atoms arranged in a hexagonal lattice and has various application fields including biological systems. in this study the in vitro effects of graphene oxide (go) on the activity of xanthine oxidase (xo) enzyme which plays a role in purine catabolism was aimed to investigate. in order to examine the effect of go on xo activity, 4 different concentrations go solution including 0.50, 1.00, 5.00 and 10.00 ppm were added to the xo reaction medium and activity values were determined spectrophotometrically at 5 different substrate concentrations (hypoxanthine). km ( michaelis-menten equation) and vmax values were determined. vmax amd km ( michaelis-menten equation) values were calculated as 0.83 μm urate/mg protein/min and 138.95 μm, respectively. when 0.50, 1.00, 5.00, 10.00 ppm go were added to the reaction medium, it was found that 36.1, 72.3, 77.1 and 84.3 percent of the xo enzyme activity was inhibited, respectively. in conclusion, a remarkable reduction was determined in both vmax and km values of the enzyme as the concentration of go goes up and it was found that enzyme inhibition remain unchanged even if we increase the substrate concentration. it showed that the inhibition type is uncompetitive inhibition.