金属和其他连接物平衡了叶绿体中的碳固定和光吸收
Xiaoxiao Shi1, Nathan M Hannon1, Arnold J Bloom1
1Department of Plant Sciences, University of California at Davis, Davis, CA.
Physiologia plantarum
|August 8, 2024
概括
植物酶Rubisco和酶活性是金属依赖的. 可以增强鲁比斯科 (Rubisco) 的功效.
科学领域:
- 生物化学 生物化学
- 植物生理学 植物生理学
- 酶学 是一种酶学.
背景情况:
- 植物酶活性受到和等结合金属的影响.
- 鲁比斯科 (Ribulose-1,5-bisphosphate carboxylase/oxygenase) 与和同等结合,具有快速的金属交换.
- 在碳代谢中Plastidial酶的作用也依赖于金属.
研究的目的:
- 在与或结合时,描述鲁比斯科和可塑性酶的动力学.
- 研究金属结合对酶特异性和反应速度的影响.
- 阐明这些酶在一种被提议的 stromal 生物化学途径中的作用.
主要方法:
- 从五种C3植物物种中净化鲁比斯科.
- 重组塑性酶动力学的特征.
- 在不同的金属条件下测量碳氧化和氧化速率的酶试验.
- 对基质和产品相互作用的分析,包括6-糖酸盐和NADP+.
主要成果:
- 与结合的Rubisco相比,结合的Rubisco在CO2/O2特异性增加了25%,Vcmax/Vomax增加了39%,而结合的Rubisco则增加了25%.
- 与结合的酶表现出前置反应 (脱碳化) 速度减慢了30%,反向反应 (碳化) 速度快了三倍.
- 通过6-糖酸盐和NADP+抑制和刺激鲁比斯科活性,随着金属结合而变化;结合的鲁比斯科将显著的RuBP转化为酸盐.
结论:
- 鲁比斯科和酶动力学受到与结合的显著改变.
- 提出了一个流体通路,其中与结合的鲁比斯科产生酸,而结合的酶将其转化为酸.
- 植物可以使用和水平来平衡碳和代谢,以应对大气中的CO2.
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