Cu centers from plastocyanin and cytochrome oxidase

Cu center of plastocyanin

Half-cell reaction:
Cu²⁺ ==> Cu³⁺ + e^-

Midpoint redox potential: E_{m, pH 7} = 360 mV
No. of electrons: z=1
No. of protons: n=0 (n=1 below pK)

The two Cu center of Cu_A of cytochrome oxidase

Half-cell reaction:
Cu_A ==> Cu_A⁺ + e^-

Midpoint redox potential: E_{m, pH 7} = 280 mV
No. of electrons: z=1
No. of protons: n=0 or 1, depending on protein, pH, pK

Cu_B at the binuclear center of cytochrome oxidase

Half-cell reaction:
Cu_B²⁺ ==> Cu_B³⁺ + e^-

Midpoint redox potential: E_{m, pH 7} = 340 mV
No. of electrons: z=1
No. of protons: n=0 or 1, depending on protein, pH, pK

©Copyright 1996, Antony Crofts, University of Illinois at Urbana-Champaign, a-crofts@uiuc.edu