Composition of the Heme Centers in Chromaffin Granule Cytochrome b561

: Electron paramagnetic resonance and circular dichroism spectra of cytochrome b561 from chromaffin granule membranes indicated a 2:1 stoichiometry of high- and low-potential hemes. Recombinant bovine cytochrome b561 expressed in a baculovirus system retained native spectroscopic characteristics and represents a promising model for further study.