PATHWAYS OF ETHYLENE BIOSYNTHESIS

Evidence is presented to show that the linolenic acid-propanal pathway is not operative in apple tissue. A mechanism for the conversion of methionine to ethylene through methional as an intermediate by a model system, consisting of flavin mononucleotide and light, is summarized. The nature of the enzymatic formation of ethylene from either α-keto-γ-methylthiobutyric acid or methional by a Mn-sulfite-phenol-oxygen-peroxidase system is described. Although the conversion of methionine to ethylene in plant tissue has been established, the data fail to support the hypothesis that methionine is converted to ethylene in plant tissues through α-keto-γ-methylthiobutyric acid and methional. Details of the pathway from methionine to ethylene remain to be elucidated. © 1969 Dr. W. Junk N. V.