Plant uncoupling mitochondrial protein activity in mitochondria isolated from tomatoes at different stages of ripening
Plant uncoupling mitochondrial protein activity in mitochondria isolated from tomatoes at different stages of ripening
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DOI：
10.1023/a:1005408809619
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发表时间：
1999-10-01
影响因子：
3
通讯作者：
Vercesi, AE
中科院分区：
文献类型：
--
作者：
Costa, ADT;Nantes, IL;Vercesi, AE
在目前的研究中，我们观察到与红色番茄(番茄)相比，从绿色番茄中分离出来的呼吸线粒体具有更高的偶联状态。绿色番茄线粒体产生足以磷酸化ADP的膜电位(Delta Psi)，而在红色番茄线粒体中，需要BSA和ATP才能使Delta Psi恢复到绿色番茄线粒体的水平。这支持了这样一种观点，即红色番茄线粒体中的这种解偶联是由植物解偶联线粒体蛋白介导的(Pump；cf，Vercesi等人，1995)。然而，绿色和红色番茄的线粒体都表现出ATP敏感的亚油酸(LA)诱导的Delta Psi下降，这为Pump在绿色番茄中也存在提供了证据。事实上，含有重组的绿色或红色番茄泵的蛋白脂质体显示了LA Uniport和LA诱导的H+转运。说明红番茄泵底物中游离脂肪酸含量较高可以解释红番茄线粒体偶联程度较低的原因。
In the present study we have observed a higher state of coupling in respiring mitochondria isolated from green as compared to red tomatoes (Lycopersicon esculentum, Mill.). Green tomato mitochondria produced a membrane potential (Delta Psi) high enough to phosphorylate ADP whereas in red tomato mitochondria, BSA and ATP were required to restore Delta Psi to the level of that obtained with green tomato mitochondria. This supports the notion that such uncoupling in 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 exhibited an ATP-sensitive linoleic acid (LA)-induced Delta Psi decrease providing evidence that PUMP is also present in green tomatoes. Indeed, proteoliposomes containing reconstituted green or red tomato PUMP showed LA uniport and LA-induced H+ transport. It is suggested that the higher concentration of free fatty acids (PUMP substrates) in red tomatoes could explain the lower coupling state in mitochondria isolated from these fruits.