| Abstract: | When methionine or one of several analogues (ethionine, homocystine, homocysteine, 2-hydroxy-4-methylthiobutyric acid or 4-methylthio-2-oxo-butyric acid) was irradiated by visible light in the presence of flavin mononucleotide (FMN), ethylene was produced in good yield 1,2]. The ethylene was derived from carbons 3 and 4 of methionine. Later Shimokawa and Kasai 3] reported that the ethyl moiety of ethionine could also be converted to ethylene by FMN and light, but these authors did not show the proportion of the ethylene derived from the ethyl moiety of ethionine. Under the optimal conditions, I have found that the ethylene derived from the ethyl moiety of ethionine represents less than 1 per cent of the total ethylene produced. The present paper describes the characteristics of ethylene production from the ethyl moiety and from carbons 3 and 4 of ethionine, and presents a mechanism to explain these reactions. |
