[[[Purification and properties of 6-phosphogluconate dehydrogenase from human erythrocytes]

6-phosphogluconate dehydrogenase was purified from human erythrocytes by chromatography on 2'5' ADP Sepharose and ammonium sulfate precipitation, to a specific activity of 28 IU/mg of protein. The enzyme binds two NADP molecules per molecule of dimer with a Kd of 6.95 microM, or only one molecule of NADPH per molecule of dimer with a Kd of 0.38 microM. The substrate has no effect on the binding of NADPH, whereas increases the binding of a coenzyme analogue, the NADP oxidized with periodate. These findings indicate a possible regulatory role for 6-phosphogluconate dehydrogenase.