Effects of ionic strength and pH on the dissociation constant between NADPH-adrenoferredoxin reductase and adrenoferredoxin.

ABSTRACT

The dissociation constant between NADPH-adrenoferredoxin reductase and adrenoferredoxin was measured at various ionic strengths (0.05-0.25) and pHs (6.6-8.2) by means of a kinetic method involving pyridoxal 5'-phosphate. For each ionic strength, the maximum dissociation constant was obtained at pH 7.4. It ranged from 8.34 (ionic strength = 0.05) to 169 nM (ionic strength = 0.25) at pH = 7.4. At each pH, the dissociation constant increased along with the increase in ionic strength.