Properties of synthesis of chlorophyll a from chlorophyll b in cucumber etioplasts.
Properties of synthesis of chlorophyll a from chlorophyll b in cucumber etioplasts.
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黄瓜黄质体中叶绿素 b 合成叶绿素 a 的特性。
DOI：
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发表时间：
1994
影响因子：
4.8
通讯作者：
A. Tanaka
中科院分区：
文献类型：
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作者：
H. Ito;S. Takaichi;H. Tsuji;A. Tanaka
当叶绿素 b 与分离的黄瓜黄质体在黑暗中孵育时，叶绿素 a 会积累。当使用[14C]叶绿素b作为叶绿素合成的底物时，形成[14C]叶绿素a，这表明叶绿素a是由外源添加的叶绿素b合成的，而不是通过内源原叶绿素内酯的不依赖于光的还原来合成。研究的反应显示最佳 pH 值为 7.5，并且需要黄质体的可溶性部分和膜部分以及 ATP。时程实验表明，叶绿素a开始积累的时间晚于叶绿素b。与香叶基香叶醇酯化的叶绿素b首先积累，但具有未氢化异戊烯基侧链的叶绿素a几乎没有积累。孵育过程中未检测到叶绿素 a。这些观察结果表明酯化的叶绿素 b 转化为叶绿素 a。这种转换对于利用叶绿素 b 合成叶绿素 a 来重建光系统将发挥重要作用。
Chlorophyll a accumulated when chlorophyllide b was incubated with isolated cucumber etioplasts in the dark. When [14C]chlorophyllide b was used as the substrate for chlorophyll synthesis, [14C]chlorophyll a was formed, showing that chlorophyll a was synthesized from the exogenously added chlorophyllide b, not by light-independent reduction of endogenous protochlorophyllide. The reaction studied showed an optimal pH of 7.5 and required both the soluble and membrane fractions of etioplasts together with ATP. Time course experiments showed that chlorophyll a began to accumulate later than chlorophyll b. Chlorophyllide b esterified with geranylgeraniol accumulated first, but there was little accumulation of chlorophyll a with an unhydrogenated prenyl side chain. No chlorophyllide a was detected during incubation. These observations indicate that esterified chlorophyll b was converted to chlorophyll a. This conversion would play an important role in the use of chlorophyll b for the synthesis of chlorophyll a in the reconstruction of photosystems.