Re: Spoiler alert

Answer: easy. As Dr. Koch published in 1938:

"The imide group, as present in guanidine and its methyl derivatives and in
the imidazole ring of histamine, definitely paralyzes oxidations even to the
point of tissue disintegration and death. This was beautifully demonstrated
after parathyroidectomy. * However, these groups may protect the
oxidation mechanism by their presence in certain oxidation co-enzymes,
(creatine phosphoric acid) by preventing these co-enzymes from being
burned in the oxidations they mediate. The imide group is able to combine
directly with catalase and peroxidase, but it is more probable that it
extinguishes catalytic activities photo-chemically by resonance induction, a
phenomenon described by the French physicist, J. Perrin.** This group
must be viewed with suspicion wherever it is found, and it brands a
compound as either a toxic quencher of the oxidations or as a protected
member of the oxidation system."