title: A spectroscopic and electrochemical study of the interaction between copper (II) glycylglycyl-L-histidine-N-methylamide and iron (III) tetra-p-sulfophenylporphine.
abstract: A binuclear complex has been produced by the reaction of an iron porphyrin (sodium tetra-p-sulfophenylporphine iron (III)-FeTPPS) with a copper metallo-tripeptide (copper (II) glycylglycyl-L-histidine-N-methylamide-CuGGH) in aqueous solution. The system has been characterized by electron spin resonance (ESR) spectroscopy, optical absorption spectroscopy, and electrochemical methods. Room-temperature ESR spectra of the copper complex and low-temperature ESR spectra of the iron porphine provide evidence for the formation of a binuclear complex. These findings are supported by absorption spectroscopy and electrochemical studies, and lead to a value of ca. 2 X 10(-3) M-1 (at room temperature) for the equilibrium constant for complex formation. The relevance of this system to the enzymic active site of mammalian cytochrome c oxidase is discussed.
mesh_terms: D001665:Binding Sites; D003300:Copper; D004563:Electrochemistry; D004578:Electron Spin Resonance Spectroscopy; D003576:Electron Transport Complex IV / Q000378:metabolism*; D007700:Kinetics; D008665:Metalloporphyrins / Q000138:chemical synthesis*; D008954:Models, Biological; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D010456:Peptides, Cyclic / Q000138:chemical synthesis*; D011048:Polarography; D011166:Porphyrins / Q000138:chemical synthesis; D013053:Spectrophotometry
chemical_list: D008665:Metalloporphyrins; D009942:Organometallic Compounds; D010456:Peptides, Cyclic; D011166:Porphyrins; C016136:tetraphenylporphine sulfonate; C046753:copper(II) glycylglycyl-histidine-N-methylamide; D003300:Copper; D003576:Electron Transport Complex IV