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 × 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.
