INTERACTION OF COMPONENTS OF CYTOCHROME-P-450 MONOOXYGENASE SYSTEM FROM LIVER-MICROSOMES .1. IMMOBILIZATION OF SOLUBILIZED AND PARTIALLY PURIFIED PROTEIN-COMPONENTS

Abstract

The method of matrix fixation was used to study the interactions between the components of the cytochrome P-450 monooxygenase from rat liver microsomes. The solubilized, isolated protein components were covalently bound to BrCN-activated Sepharose in different ways and the N-demethylase activity was determined. In each case of fixation a certain amount of activity could be determined. The degree of activity varied in dependence on the sequence and number of bound components. The activity compared with the reconstituted soluble system decreased after single fixation of NADPH-cytochrome P-450 reductase (40%) and cytochrome P-450 (23%). After sequential fixation the 1st component cytochrome P-450 (33%) and the 1st component NADPH-cytochrome P-450 reductase (8%) were decreased. Simultaneous fixation of both components yielded a lower activity. The activity is probably influenced by some kind of self-assembly.