MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824.
Plant Physiol. 1979 Apr;63(4):639-42. doi: 10.1104/pp.63.4.639.
Stem sections of etiolated pea seedlings (Pisum sativum L. cv. Alaska) were incubated overnight on tracer amounts of l-[U-(14)C]methionine and, on the following morning, on 0.1 millimolar indoleacetic acid to induce ethylene formation. Following the overnight incubation, over 70% of the radioactivity in the soluble fraction was shown to be associated with S-methylmethionine (SMM). The specific radioactivity of the ethylene evolved closely paralleled that of carbon atoms 3 and 4 of methionine extracted from the tissue and was always higher than that determined for carbon atoms 3 and 4 of extracted SMM.Overnight incubation of pea stem sections on 1 millimolar methionine enhanced indoleacetic acid-induced ethylene formation by 5 to 10%. Under the same conditions, 1 millimolar homocysteine thiolactone increased ethylene synthesis by 20 to 25%, while SMM within a concentration range of 0.1 to 10 millimolar did not influence ethylene production. When unlabeled methionine or homocysteine thiolactone was applied to stem sections which had been incubated overnight in l-[U-(14)C]methionine, the specific radioactivity of the ethylene evolved was considerably lowered. Application of unlabeled SMM reduced the specific radioactivity of ethylene only slightly.
将黄化豌豆幼苗（Pisum sativum L. cv. Alaska）的茎段在示踪量的 l-[U-(14)C]蛋氨酸上培养过夜，第二天早上在 0.1 毫摩尔吲哚乙酸上培养以诱导乙烯形成。在过夜孵育后，可溶部分中超过 70%的放射性与 S-甲基蛋氨酸（SMM）有关。释放出的乙烯的比放射性与从组织中提取的蛋氨酸的碳原子 3 和 4 的比放射性密切平行，并且始终高于从提取的 SMM 的碳原子 3 和 4 确定的比放射性。在 1 毫摩尔蛋氨酸上培养豌豆茎段过夜可增强吲哚乙酸诱导的乙烯形成 5 至 10%。在相同条件下，1 毫摩尔同型半胱氨酸硫内酯使乙烯合成增加 20 至 25%，而 0.1 至 10 毫摩尔范围内的 SMM 不影响乙烯的产生。当未标记的蛋氨酸或同型半胱氨酸硫内酯应用于在 l-[U-(14)C]蛋氨酸中孵育过夜的茎段时，释放出的乙烯的比放射性大大降低。未标记 SMM 的应用仅略微降低了乙烯的比放射性。
