Purification of 6-phosphogluconate dehydrogenase from chicken liver and investigation of some kinetic properties

6-Phosphogluconate (6PG) dehydrogenase (EC 1.1.1.44,; 6PGD) was purified from chicken liver; some kinetic and characteristic properties of the enzyme were investigated. The purification procedure consisted of four steps: preparation of the hemolysate, ammonium sulfate precipitation, 2'.5'-ADP Sepharose 4B affinity chromatography, and Sephadex G-200 gel filtration chromatography. Thanks to the four consecutive procedures, product having a specific activity of 61 U (mg proteins)(-1), was purified 344-fold with a yield of 5.57%. Optimum pH. stable pH. optimum temperature, and K-m and V-max values for NADP+ and 6PG substrates were determined for the enzyme. Molecular weight of the enzyme was also determined by Sephadex G-200 gel filtration chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). In addition, K-i values and inhibition types were estimated by means of Lineweaver-Burk graphs obtained for NADPH and CO2 products.