del Río Luis A, Corpas F Javier, Sandalio Luisa M, Palma José M, Gómez Manuel, Barroso Juan B
Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidín, CSIC, Apartado 419, E-18080 Granada, Spain.
J Exp Bot. 2002 May;53(372):1255-72.
Peroxisomes are subcellular organelles with an essentially oxidative type of metabolism. Like chloroplasts and mitochondria, plant peroxisomes also produce superoxide radicals (O2*(-)) and there are, at least, two sites of superoxide generation: one in the organelle matrix, the generating system being xanthine oxidase, and another site in the peroxisomal membranes dependent on NAD(P)H. In peroxisomal membranes, three integral polypeptides (PMPs) with molecular masses of 18, 29 and 32 kDa have been shown to generate radicals O2*(-). Besides catalase, several antioxidative systems have been demonstrated in plant peroxisomes, including different superoxide dismutases, the ascorbate-glutathione cycle, and three NADP-dependent dehydrogenases. A CuZn-SOD and two Mn-SODs have been purified and characterized from different types of peroxisomes. The four enzymes of the ascorbate-glutathione cycle (ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase) as well as the antioxidants glutathione and ascorbate have been found in plant peroxisomes. The recycling of NADPH from NADP(+) can be carried out in peroxisomes by three dehydrogenases: glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, and isocitrate dehydrogenase. In the last decade, different experimental evidence has suggested the existence of cellular functions for peroxisomes related to reactive oxygen species (ROS), but the recent demonstration of the presence of nitric oxide synthase (NOS) in plant peroxisomes implies that these organelles could also have a function in plant cells as a source of signal molecules like nitric oxide (NO*), superoxide radicals, hydrogen peroxide, and possibly S-nitrosoglutathione (GSNO).
过氧化物酶体是具有基本氧化代谢类型的亚细胞细胞器。与叶绿体和线粒体一样，植物过氧化物酶体也会产生超氧自由基（O2*(-)），并且至少有两个超氧产生位点：一个在细胞器基质中，产生系统是黄嘌呤氧化酶，另一个位点在过氧化物酶体膜上，依赖于NAD(P)H。在过氧化物酶体膜中，已证明三种分子量分别为18、29和32 kDa的整合多肽（PMPs）会产生O2*(-)自由基。除了过氧化氢酶外，植物过氧化物酶体中还证明了几种抗氧化系统，包括不同的超氧化物歧化酶、抗坏血酸-谷胱甘肽循环和三种NADP依赖性脱氢酶。已从不同类型的过氧化物酶体中纯化并鉴定出一种铜锌超氧化物歧化酶和两种锰超氧化物歧化酶。在植物过氧化物酶体中发现了抗坏血酸-谷胱甘肽循环的四种酶（抗坏血酸过氧化物酶、单脱氢抗坏血酸还原酶、脱氢抗坏血酸还原酶和谷胱甘肽还原酶）以及抗氧化剂谷胱甘肽和抗坏血酸。NADPH从NADP(+)的循环可以通过三种脱氢酶在过氧化物酶体中进行：葡萄糖-6-磷酸脱氢酶、6-磷酸葡萄糖酸脱氢酶和异柠檬酸脱氢酶。在过去十年中，不同的实验证据表明过氧化物酶体与活性氧（ROS）相关的细胞功能的存在，但最近在植物过氧化物酶体中一氧化氮合酶（NOS）的存在证明意味着这些细胞器在植物细胞中也可能作为信号分子如一氧化氮（NO*）、超氧自由基、过氧化氢以及可能的S-亚硝基谷胱甘肽（GSNO）的来源发挥作用。
