Cytochrome P-450cam

Apocytochrome P-450cam in a reconstitutable form was prepared from the purified native holoenzyme by acid-acetone treatment at -20°. The prosthetic group is ferriprotoporphyrin IX, identified by the pyridine hemochromogen spectrum and by co-chromatography of authentic and isolated samples. The apocytochrome is not protected by the substrate and is less stable at -20°. The catalytically active holocytochrome P-450cam has been prepared from the apoenzyme in greater than 66% yield via P-420 on addition of equimolar heme in 4% methanol-phosphate buffer, pH 7.0, followed by a cysteine-glycerol treatment.