Biosynthesis of ethylene. Ethylene formation from methional by horseradish peroxidase

Ethylene is rapidly formed from methional by horseradish peroxidase, Mn⁺, SO₃²⁻, and a specific phenol, or by horseradish peroxidase, SO₃²⁻, catalytical amounts of hydrogen peroxide, and a specific phenol. The active phenols include some monohydric phenols and resorcinol. Ethylene formation is inhibited by o-dihydric phenols, Cu⁺⁺, or metal chelators. Ethylene formation accompanies the aerobic oxidation of sulfite during the reactions, and those inhibitors which inhibit ethylene formation also inhibit the enzymic oxidation of sulfite. A mechanism accounting for the formation of ethylene and the physiological significance of this reaction in relation to the biosynthesis of ethylene in plants is discussed.