Oxidation of heme proteins by copper(II) complexes. Rates and mechanism of the copper catalysed autoxidation of cytochrome c, myoglobin and hemoglobin

✍ Scribed by Mary Ann Agustin; John K. Yandell

• Publisher: Elsevier Science
• Year: 1979
• Tongue: English
• Weight: 811 KB
• Volume: 37
• Category: Article
• ISSN: 0020-1693
• DOI: 10.1016/s0020-1693(00)95512-9

✦ Synopsis

The mechanism of the a&oxidation of ferrocytochrome c catalysed by some copper complexes has been established. In most cases the rate determining step was found to be the one electron oxidation of the cytochrome by the copper(H) species, which was followed by the rapid reoxidation of the resulting Cu(I) complexes by molecular oxygen. The rate constants for the electron transfer reactions of several copper complexes with ferrocytochrome c, myoglobin and hemoglobin have been measured at 25 "C. It was shown that these rates for the copper complexes, as well as those for several other oxidants, are consistent with simple outer sphere electron transfer through the heme edge for all the heme proteins The redox potential of the reacting species was found to be the dominant factor in determining the relative rate of the electron transfer reactions. This enables the catalytic activity of different copper complexes to be predicted.