Cobalt-substituted cytochrome P-450cam.
Reconstitution of the apo-cytochrome with cobalt protoporphyrin provides a faithful P-450cam analogue as characterized by optical, ligand-binding, and enzymatic parameters. The thiol and cyanide complexes exhibit Soret "hyper" spectra, not previously observed in cobalt porphyrins. Substrate-induced spectral changes and limited stereospecific hydroxylation activity are retained in the cobalt P-450cam. The EPR (electron paramagnetic resonance) spectra of the reduced cobaltous protein indicate clearly an endogenous axial ligand other than a nitrogenous base and support an assignment of thiolate coordination. A thiolate ligand is also indicated by EPR measurements in the oxygenated cobaltous analogue. By analogy, these studies suggest that the native ferrous and oxygenated P-450cam states retain a thiolate axial ligand.
D001059:Apoproteins; D002164:Camphor / Q000378:metabolism; D055598:Chemical Phenomena; D002621:Chemistry; D003035:Cobalt; D003577:Cytochrome P-450 Enzyme System; D004578:Electron Spin Resonance Spectroscopy; D010084:Oxidation-Reduction; D011524:Protoporphyrins; D011549:Pseudomonas / Q000201:enzymology; D013057:Spectrum Analysis
D001059:Apoproteins; D011524:Protoporphyrins; D003035:Cobalt; C007095:cobaltiprotoporphyrin; D002164:Camphor; D003577:Cytochrome P-450 Enzyme System