JBC, Vol. 250, Issue 6, 2095-2098, Mar, 1975
Complexation of iron hexacyanides by cytochrome c. Evidence for electron exchange at the exposed heme edge
E. Stellwagen and R. D. Cass
Electrostatic binding of at least two anionic iron hexacyanides to cationic
horse heart cytochrome c was demonstrated by equilibrium dialysis
measurements. No binding was detected following trifluoroacetylation of all
of the 19 lysine residues. Replacement of the natural heme iron ligand
methionine 80 by the alternative intrinsic ligand lysine 79 but not the
extrinsic ligand imidazole resulted in the loss of one hexacyanide binding
site. It is proposed that this site is located at the exposed heme edge and
is functional in electron exchange.