The inhibitory impact of glutathione (GSH) and ascorbic acid (vitamin C) compounds on glucose-6-phosphate dehydrogenase (G6PD) enzyme purified from sheep liver

Glucose-6-phosphate dehydrogenase (G6PD) is an enzyme with many essential biochemical functions. However, in various cancer diseases, increased activity of G6PD causes cancer cells to grow, so G6PD inhibitors have become a significant area of research in cancer treatment. Here, G6PD was purified 4530-fold with affinity chromatography using 2’,5′-ADP Sepharose 4B from sheep liver. The effects of reduced glutathione (GSH) and ascorbic acid (vitamin C) on G6PD activity were explored. GSH and ascorbic acid showed a significant inhibitory effect on G6PD, and IC50 values were found as 0.37 µM and 34.66 µM, respectively. The inhibition type from Lineweaver-Burk plots of these compounds was identified as non-competitive inhibition. The Ki values of GSH and ascorbic acid were calculated as 0.48 µM and 30.47 µM, respectively. In this study, it was observed that GSH and ascorbic acid antioxidant compounds exhibit an inhibitory effect on G6PD and may be protective and preventive against cancer.