ETHYLENE BIOSYNTHESIS - IDENTIFICATION OF 1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID AS AN INTERMEDIATE IN THE CONVERSION OF METHIONINE TO ETHYLENE
ETHYLENE BIOSYNTHESIS - IDENTIFICATION OF 1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACID AS AN INTERMEDIATE IN THE CONVERSION OF METHIONINE TO ETHYLENE
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DOI：
10.1073/pnas.76.1.170
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发表时间：
1979-01-01
影响因子：
11.1
通讯作者：
YANG, SF
中科院分区：
文献类型：
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作者：
ADAMS, DO;YANG, SF
L-[U-14 C]甲醇饲喂苹果[Malus sylvestris cv.当组织在空气中孵育时，[Golden Delicious]组织有效地转化为乙烯。然而，在N中，它没有代谢为乙烯，而是转化为1-氨基环丙烷-1-羧酸（ACC）。当苹果组织与L-[甲基-14C]蛋氨酸或L-[35 S]蛋氨酸和培养在N，放射性随后发现在甲基硫代核糖。这表明甲硫氨酸首先转化为S-腺苷甲硫氨酸，S-腺苷甲硫氨酸又被片段化为ACC和甲硫腺苷。然后甲硫腺苷水解为甲硫核糖。ACC是甲硫氨酸向乙烯转化的中间体，标记ACC在空气中培养的苹果组织中能有效地转化为乙烯，未标记ACC的存在大大降低了标记甲硫氨酸向乙烯的转化，但未标记甲硫氨酸的存在对标记ACC向乙烯的转化影响不大;和2-氨基-4-（2“-氨基乙氧基）反式-3-丁烯酸，磷酸吡哆醛介导的酶反应的有效抑制剂，极大地抑制甲硫氨酸向乙烯的转化，但不抑制ACC向乙烯的转化。这些数据表明苹果组织中乙烯生物合成途径的下列序列：甲硫氨酸→S-腺苷蛋氨酸ACC →乙烯。一个可能的机制占这些反应。
L-[U-14C]Methionine fed to apple [Malus sylvestris cv. Golden Delicious] tissue was efficiently converted to ethylene when the tissue was incubated in air. In N, however, it was not metabolized to ethylene but was instead converted to 1-aminocyclopropane-1-carboxylic acid (ACC). When apple tissues were fed with L-[methyl-14C]methionine or L-[35S]methionine and incubated in N, radioactivity was found subsequently in methylthioribose. This suggests that methionine is first converted to S-adenosylmethionine which is in turn fragmented to ACC and methylthioadenosine. Methylthioadenosine is then hydrolyzed to methylthioribose. ACC is an intermediate in the conversion of methionine to ethylene based on the following observations: Labeled ACC was efficiently converted to ethylene by apple tissue incubated in air; the conversion of labeled methionine to ethylene was greatly decreased in the presence of unlabeled ACC, but the conversion of labeled ACC to ethylene was little affected by the presence of unlabeled methionine; and 2-amino-4-(2''-aminoethoxy)trans-3-butenoic acid, a potent inhibitor of pyridoxal phosphate-mediated enzyme reactions, greatly inhibited the conversion of methionine to ethylene but did not inhibit conversion of ACC to ethylene. These data indicate the following sequence for the pathway of ethylene biosynthesis in apple tissue: methionine .fwdarw. S-adenosylmethionine .fwdarw. ACC .fwdarw. ethylene. A possible mechanism accounting for these reactions is presented.