Carbon monoxide and nitrogen monoxide ligand dynamics in synthetic heme and heme-copper complex systems.
Intermolecular nitrogen monoxide (*NO) and carbon monoxide (CO) transfer from iron to copper and back, a phenomenon not previously observed, has been accomplished by employing transient-absorbance laser flash photolysis methods. A 1:1 heme/copper component system consisting of a six-coordinate ferrous species, F(8)Fe(II)(CO)(DCIM) or F(8)Fe(II)(NO)(thf) [F(8) = tetrakis(2,6-difluorophenyl)porphyrinate(2-); DCIM = 1,5-dicyclohexylimidazole; thf = tetrahydrofuran], and two ligand-copper(I) complexes, one with tridentate [(Bz)L = (benzyl)bis(2-pyridylmethyl)amine] and one with tetradentate coordination [(Py)L = tris(2-pyridylmethyl)amine], was utilized. The results suggest a lower affinity for NO versus CO binding to copper(I) and a higher rate for NO versus CO binding to heme. In fact, the latter event has been observed in cytochrome c oxidase aa(3).
Lucas
Heather R
HR
Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218, USA.
Meyer
Gerald J
GJ
Karlin
Kenneth D
KD
D002248:Carbon Monoxide / Q000737:chemistry*; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006418:Heme / Q000737:chemistry*; D007700:Kinetics; D008024:Ligands; D009569:Nitric Oxide / Q000737:chemistry*; D010782:Photolysis; D013057:Spectrum Analysis
D008024:Ligands; D009569:Nitric Oxide; D006418:Heme; D003300:Copper; D002248:Carbon Monoxide