Plant Uncoupling Mitochondrial Protein Activity in Mitochondria Isolated from Tomatoes at Different Stages of Ripening |
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Authors: | Alexandre D T Costa Iseli L Nantes Petr Ježek Adílson Leite Paulo Arruda Anibal E Vercesi |
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Institution: | (1) Department of Membrane Transport Biophysics, Institute of Physiology, Prague, Czech Republic;(2) Departamento de Patologia Clínica (NMCE), Faculdade de Ciências Meédicas, Universidade Estadual de Campinas, CEP, 13083-970 Campinas, SP, Brazil;(3) Present address: Centro Interdisciplinar de Investigação Bioquímica, Universidade de Mogi das Cruzes, CEP 08780-911 Mogi das Cruzes, SP, Brazil;(4) Centro de Biologia Molecular e Engenharia Gene;aatica, Universidade Estadual de Campinas, CEP 13083 - 970 Campinas, SP, Brazil |
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Abstract: | In the present study we have observed a higher state of coupling in respiring mitochondriaisolated from green as compared to red tomatoes (Lycopersicon esculentum, Mill.). Greentomato mitochondria produced a membrane potential (![Delta](/content/m86m79115n3rg752/xxlarge916.gif) ) high enough to phosphorylate ADP,whereas in red tomato mitochondria, BSA and ATP were required to restore ![Delta](/content/m86m79115n3rg752/xxlarge916.gif) to the levelof that obtained with green tomato mitochondria. This supports the notion that such uncouplingin red tomato mitochondria is mediated by a plant uncoupling mitochondrial protein (PUMP;cf. Vercesi et al., 1995). Nevertheless, mitochondria from both green and red tomatoes exhibitedan ATP-sensitive linoleic acid (LA)-induced ![Delta](/content/m86m79115n3rg752/xxlarge916.gif) decrease providing evidence that PUMP isalso present in green tomatoes. Indeed, proteoliposomes containing reconstituted green or redtomato PUMP showed LA uniport and LA-induced H+ transport. It is suggested that the higherconcentration of free fatty acids (PUMP substrates) in red tomatoes could explain the lowercoupling state in mitochondria isolated from these fruits. |
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Keywords: | Plant uncoupling mitochondrial protein (PUMP) fatty acids ripening Lycopersicon esculentum |
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