Protein degradation in C3 and C4 plants with particular reference to ribulose bisphosphate carboxylase and glycolate oxidase
Protein degradation in C3 and C4 plants with particular reference to ribulose bisphosphate carboxylase and glycolate oxidase
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DOI：
10.1093/jexbot/49.322.807
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发表时间：
1998-05-01
影响因子：
6.9
通讯作者：
Teixeira, AR
中科院分区：
文献类型：
--
作者：
Esquivel, MG;Ferreira, RB;Teixeira, AR
由于缺乏适当的方法，确定蛋白质的降解特性很困难，特别是在叶蛋白的情况下，先前的研究表明，核酮糖二磷酸羧化酶（RuBP 羧化酶；EC 4.1.1.39）的蛋白水解作用在 C-3 和 C-4 植物中可能根本不同。为了检验这一假设，总可溶性蛋白、RuBP 羧化酶和乙醇酸氧化酶（EC 1.1.3.1)在完整的C、(Triticum aestivum L.)和C-4(Zea mays L.和Sorghum bicolor L.)植物的第二叶中进行了测量。所采用的方法包括有效的程序来标记叶蛋白，使用双标记方法来测量蛋白质降解以及对所研究的标记蛋白质进行单步纯化，RuBP羧化酶在所有研究的植物中都受到连续降解，其降解率对于玉米来说较高，对于普通小麦来说是中等的，对于二色小麦来说是较低的，当将RuBP羧化酶降解速率与总可溶性蛋白的降解速率进行比较时，获得了所检查植物物种的差异模式：玉米的RuBP羧化酶降解速率比总可溶性蛋白的降解速率更快，小麦和高粱的降解速率相似，但是，所研究的三种植物中RuBP羧化酶的蛋白水解速率远低于乙醇酸氧化酶的降解速率。获得的结果表明，在研究条件下，植物 RuBP 羧化酶的降解特性与乙醇酸氧化酶的降解特性一样，具有物种特异性，在某种程度上表明它们不依赖于所考虑物种的光合代谢类型（C-3 或 C-4）。
Determining the degradation characteristics of proteins is difficult due to the lack of appropriate methodologies, particularly in the case of leaf proteins, Previous studies suggest that ribulose bisphosphate carboxylase (RuBP carboxylase; EC 4.1.1.39) proteolysis may be fundamentally different in C-3 and C-4 plants, To test this hypothesis, the relative degradation rates of the total soluble protein, RuBP carboxylase and glycolate oxidase (EC 1.1.3.1) in the second leaves of intact C, (Triticum aestivum L.) and C-4 (Zea mays L. and Sorghum bicolor L.) plants was measured. The methodology utilized involved an efficient procedure to label the leaf proteins, the use of a double-labelling method to measure protein degradation and a single-step purification of the labelled proteins under study, RuBP carboxylase is subjected to continuous degradation in all plants investigated, Its rate of degradation is higher for Z. mays, intermediate for T. aestivum and lower for S. bicolor, When the rate of RuBP carboxylase degradation was compared with that of the total soluble protein a differential pattern was obtained for the plant species examined: whereas maize presents a faster rate of RuBP carboxylase degradation than of the total soluble protein, wheat and sorghum show similar rates, However, the rate of RuBP carboxylase proteolysis in the three plant species studied is much lower than the rate of glycolate oxidase degradation. The results obtained indicate that, under the conditions of study, the degradation characteristics of plant RuBP carboxylase, as those of glycolate oxidase, are species specific, in a way suggesting that they do not depend on the type of photosynthetic metabolism of the species considered (C-3 or C-4).