California State University, Northridge, entitled “Assay for Superoxide Dismutase Activity Using the Enzyme Inhibition of the Oxidation of Epinephrine”

“[a]s O2 builds in the solution, the formation of adrenochrome accelerates because O2 also reacts with epinephrine to form adrenochrome. Toward the end of the reaction, when the epinephrine is consumed, the adrenochrome formation slows down.”