STUDIES ON THE ASSOCIATION OF P-450LM2 WITH NADPH-CYTOCHROME P-450 REDUCTASE AND WITH TRYPTIC PEPTIDES DERIVED FROM THE REDUCTASE

Abstract

Trypsinolysis of purified rabbit liver microsomal NADPH-cytochrome P-450 reductase yields a large, soluble fragment capable of reducing cytochrome c but not P-450 LM , and a small fragment or “tail peptide” which has been isolated and shown by its solubility and amino acid composition to be hydrophobic in nature. The large fragment is unable to bind to the cytochrome, as shown by gel exclusion chromatography and difference spectrophotometry. These and other experiments indicate that the hydrophobic tail peptide is required for formation of a functional complex between the reductase and P-450 LM in the reconstituted hydroxylation system.