Structural comparison between the trout and mammalian hydrophilic domain of NADPH-cytochrome P-450 reductase.

The isolation of the protease-solubilized NADPH-cytochrome P-450 reductase from trout liver and its properties are described. The sequence of the "hydrophilic domain" [protease-solubilized NADPH-cytochrome P-450 reductase from trout (residues Lys56-Ser678)] is reported. The CNBr fragments of the trout "hydrophilic domain" and their proteolytic subpeptides were sequenced. The CNBr fragments were aligned by homology to the reported sequence of the porcine NADPH-cytochrome P-450 reductase. The structures of the mammalian and the trout NADPH-cytochrome P-450 reductases were compared. Stretches with high exchange rates between the pig and trout reductase were found at the NH2 and the COOH terminal regions of the hydrophilic domain.