Definition of cytochrome c binding domains by chemical modification. Interaction of horse cytochrome c with beef sulfite oxidase and analysis of steady state kinetics.

Enzymic conversion of inorganic sulfite to sulfate is the terminal step in sulfur catabolism in higher animals (1-6) and has also been observed in plants and bacteria (7-11). The physiological significance of this reaction is apparent from the severe pathophysiological consequences of its absence (6, 12, 13). Sulfite oxidase has been extensively purified (1-4, 14, 15) and