Plant hormone ethylene is a Norrish type II product from enzymically generated triplet 1-butanal.

Knudsen, F D; Campa, A; Stefani, H A; Cilento, G · Proc Natl Acad Sci U S A · 1994

basic_science · Level V

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Abstract

The peroxidase-catalyzed aerobic oxidation of a linear aldehyde, leading to the next lower homologue in the triplet state, is accompanied by Norrish type II product ethylene when the substrate is pentanal. This system appears to provide an example of "photobiochemistry without light" because ethylene is a plant hormone and is formed in lipid peroxidation when the recurrent oxidation of linear aldehydes occurs.