Stellacyanin self-exchange rate constants

Self-exchange rate constants have been determined for P. aeruginosa and A. dinitrificans azurin (63) and T. versutus amicyanin (68) by NMR line broadening, and for Rhus vernicifera stellacyanin by EPR... [Pg.401]

Given the measured self-exchange rate constant for stellacyanin (kn ... [Pg.342]

X 10 s ), the Marcus cross relation (Equation 6.26a) can be used to calculate the reaction rates for the reduction of Cu -stellacyanin by Fe(EDTA) and the oxidation of Cu -stellacyanin by Co(phen)3 +. E°(Cu ) for stellacyanin is 0.18 V vs. NHE, and the reduction potentials and self-exchange rate constants for the inorganic reagents are given in Table 6.3. For relatively small AE° values,/12 is 1 here a convenient form of the Marcus cross relation is log k,2 = 0.5[log kn + log 22 + 16.9AE°2]. Calculations with kn, 22, and AE°2 from experiments give k,2 values that accord quite closely with the measured rate constants. [Pg.342]

Stellacyanin from R. vernicifera has been modified by coordination of [Ru(NH3)5] " to surface histidines at positions 32 and 100. The rate constant and activation parameters for the intramolecular electron transfer from Ru(II) to the stellacyanin Cu(II) have been determined, and were found to be in good agreement with Marcus theory. The replacement of methionine by lysine at position 44 in P. aeruginosa azurin by site-directed mutagenesis results in a decrease in the Cu(I)/Cu(II) electron self-exchange rate constant (36 °C) from 1.3xl0 M... [Pg.29]

Big Chemical Encyclopedia