Mateos Rosa M, León Ana M, Sandalio Luisa M, Gómez Manuel, del Río Luis A, Palma José M
Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental del Zaidin, CSIC, Apartado 419, E-18080 Granada, Spain.
J Plant Physiol. 2003 Dec;160(12):1507-16. doi: 10.1078/0176-1617-01008.
Pepper is a vegetable of importance in human nutrition. Currently, one of the most interesting properties of natural products is their antioxidant content. In this work, the purification and characterisation of peroxisomes from fruits of a higher plant was carried out, and their antioxidative enzymatic and non-enzymatic content was investigated. Green and red pepper fruits (Capsicum annuum L., type Lamuyo) were used in this study. The analysis by electron microscopy showed that peroxisomes from both types of fruits contained crystalline cores which varied in shape and size, and the presence of chloroplasts and chromoplasts in green and red pepper fruits, respectively, was confirmed. Peroxisomes were purified by differential and sucrose density-gradient centrifugations. In the peroxisomal fractions, the activity of the photorespiration, beta-oxidation and glyoxylate cycle enzymes, and the ROS-related enzymes catalase, superoxide dismutase, xanthine oxidase, glutathione reductase and NADP(+)-dehydrogenases, was determined. Most enzymes studied had higher specific activity and protein content in green than in red fruits. By native PAGE and western blot analysis, the localisation of a Mn-SOD in fruit peroxisomes was demonstrated. The ascorbate and glutathione levels were also determined in crude extracts and in peroxisomes purified from both green and red peppers. The total ascorbate content (200-220 mg per 100 g FW) was similar in crude extracts from the two types of fruits, but higher in peroxisomes from red peppers. The glutathione concentration was 2-fold greater in green pepper crude extracts than in red fruits, whereas peroxisomes from both tissues showed similar values. The presence in pepper peroxisomes of different antioxidative enzymes and their corresponding metabolites implies that these organelles might be an important pool of antioxidants in fruit cells, where these enzymes could also act as modulators of signal molecules (O2*-, H202) during fruit maturation.
辣椒是人类营养中一种重要的蔬菜。目前，天然产物最有趣的特性之一是其抗氧化成分。在这项工作中，对一种高等植物果实中的过氧化物酶体进行了纯化和表征，并研究了其抗氧化酶和非酶成分。本研究使用了青椒和红椒果实（辣椒属，拉穆约类型）。电子显微镜分析表明，两种果实的过氧化物酶体都含有形状和大小各异的结晶核心，并且分别证实了青椒和红椒果实中叶绿体和有色体的存在。通过差速离心和蔗糖密度梯度离心对过氧化物酶体进行纯化。在过氧化物酶体组分中，测定了光呼吸、β-氧化和乙醛酸循环酶以及与活性氧相关的酶过氧化氢酶、超氧化物歧化酶、黄嘌呤氧化酶、谷胱甘肽还原酶和NADP(+)-脱氢酶的活性。大多数研究的酶在青椒中的比活性和蛋白质含量高于红椒。通过非变性聚丙烯酰胺凝胶电泳和蛋白质印迹分析，证明了锰超氧化物歧化酶在果实过氧化物酶体中的定位。还测定了从青椒和红椒中提取的粗提物以及纯化的过氧化物酶体中的抗坏血酸和谷胱甘肽水平。两种果实粗提物中的总抗坏血酸含量（每100克鲜重200 - 220毫克）相似，但红椒过氧化物酶体中的含量更高。青椒粗提物中的谷胱甘肽浓度比红椒果实中的高2倍，而两种组织的过氧化物酶体显示出相似的值。辣椒过氧化物酶体中存在不同的抗氧化酶及其相应的代谢物，这意味着这些细胞器可能是果实细胞中抗氧化剂的重要储存库，在果实成熟过程中这些酶也可能作为信号分子（超氧阴离子、过氧化氢）的调节剂。
