中文摘要：

联乙烯还原酶（DVR）将各种叶绿素中间物质的8-乙烯基转化为乙基,是叶绿素生物合成必不可少的一个关键酶。迄今已在高等植物中检测到5种DVR活性。水稻和玉米的重组DVR蛋白能将联乙烯叶绿素a、叶绿素酸酯a、原叶绿素酸酯a、镁原卟啉Ⅸ单甲酯和镁原卟啉Ⅸ分别转化为相应的单乙烯物质,从而证实了这5种DVR活性。在高等植物中各种DVR活性是由一个基因编码的具有广谱底物专化性的DVR蛋白所催化,但来源于不同物种的DVR蛋白的催化活性可能具有极显著的差异,并且即使是同一个DVR蛋白,对不同的联乙烯底物也可能具有显著不同的催化活性。在此基础上,提出了＂源于一个联乙烯还原酶的叶绿素生物合成多分支路径＂假说。该文对近年来国内外有关高等植物叶绿素生物合成途径中联乙烯中间物质与联乙烯还原酶活性、联乙烯还原酶基因的克隆及重组酶活性检测、联乙烯还原酶的数目与叶绿素生物合成的多分支路径等方面的研究进展进行综述,并讨论了有待进一步探讨的若干问题。

英文摘要：

Divinyl reductase （DVR） converts 8-vinyl groups on various chlorophyll intermediates to ethyl groups,which is indispensable for chlorophyll biosynthesis. In the past decades, five DVR activities have been detected in higher plants. Recently, the results suggested that recombinant DVR proteins of rice and maize could convert divinyl chlorophyll a, chlorophyllide a, protoehlorophyllide a, Mg protoporphyrin IX monmethyl ester and Mg-protoporphyrin IX into corresponding monovinyl compounds, respectively,which confirmed the five DVR activities. Moreover, the data suggested that a single DVR with broad substrate specificity encoded by one gene was responsible for reducing the 8-vinyl groups of various chlorophyll intermediates in higher plants, but DVR proteins from different species had quite different reductive activities on the same or on different substrates even though they are homologous. In addition, it was proposed the muhibranched chlorophyll biosynthetic pathways resulting from a single DVR protein in higher plants. In this review,we briefly introduced the advances on divinyl intermediates and DVR activities in chlorophyll biosynthesis,cloning of DVR genes and enzymatic assays of recombinant DVR proteins, number of DVRenzymes and multibranched chlorophyll biosynthetic pathways in higher plants. Meanwhile, we also dis cussed some problems to be further probed.