Solution to PS 4 #7
a) Oxygen binds to Fe3+ of a3 in Complex IV in
order to accept electrons. It is prevented from doing so by CN-
which binds to the same Fe ion.
b) The methemoglobin generated by nitrite treatment competes with cytochrom
a3 for the CN- ions. This competition lowers the
CN- ion concentration, . Lowered CN- concetrations
mean that more cytochrome a3 is free to bind oxygen and this
lessens the inhibition of the electron transport chain.
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