REGULATION OF VIOLAXANTHIN DE-EPOXIDASE ACTIVITY BY PH AND ASCORBATE CONCENTRATION
REGULATION OF VIOLAXANTHIN DE-EPOXIDASE ACTIVITY BY PH AND ASCORBATE CONCENTRATION
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DOI：
10.1007/bf00032588
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发表时间：
1995-08-01
影响因子：
3.7
通讯作者：
AKERLUND, HE
中科院分区：
文献类型：
--
作者：
BRATT, CE;ARVIDSSON, PO;AKERLUND, HE
在分离的类囊体中和部分纯化后，研究了紫黄质脱环氧化酶的活性与pH和抗坏血酸盐浓度的关系。我们证明，紫黄素脱环氧酶具有K-抗坏血酸，这是强烈依赖于pH值为10，2.5，1.0和0.3 mM，在pH值为6.0，5.5，5.0和4.5，分别为m。对于抗坏血酸的酸形式，这些值可以表示为单个K-m +/- 0.1 +/- 0.02 mM。从类囊体通过超声处理的蛋白质的释放也被发现是强烈的pH依赖性与4的协同性相对于质子和pH值为6.7的pH6.7的pH6.7点。这些结果可以解释一些文献中报道的差异，并提供了一个更一致的看法，玉米黄质在体内形成。
The activity of violaxanthin de-epoxidase has been studied both in isolated thylakoids and after partial purification, as a function of pH and ascorbate concentration. We demonstrate that violaxanthin de-epoxidase has a K-m for ascorbate that is strongly dependent on pH, with values of 10, 2.5, 1.0 and 0.3 mM at pH 6.0, 5.5, 5.0 and 4.5, respectively. These values can be expressed as a single K-m +/- 0.1 +/- 0.02 mM for the acid form of ascorbate. Release of the protein from the thylakoids by sonication was also found to be strongly pH dependent with a cooperativity of 4 with respect to protons and with an inflexion point at pH 6.7. These results can explain some of the discrepancies reported in the literature and provide a more consistent view of zeaxanthin formation in vivo.