CN stops Ox Phos in the mitochondria.
The action of cyanides and hydrocyanic acid on living animals, in particular on mammals, is attributed by and large to their irreversible reaction with the iron ions in the blood. This effects the assimilation and transportation of oxygen in the blood to the various parts of the body, which has dire effect on the functioning. Other mechanisms were proposed and are believed to play a strong role in cyanide toxicity, however, the rapid toxicity is believed to be due to the cyanides interrupting the absorption and assimilation of oxygen
They may have found something new, my biochemistry is 40 years old, but chemsee.com is basically what I remember from biochem.
your response is also detailed in some articles. It appears they have found additional info on the biochemical reaction since I had biochem. It’s also possible I forgot. Either way, I stand corrected!