OXIDATION OF CITRATE ISOCITRATE + CIS-ACONITATE BY ISOLATED MITOCHONDRIA
OXIDATION OF CITRATE ISOCITRATE + CIS-ACONITATE BY ISOLATED MITOCHONDRIA
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DOI：
10.1042/bj0900225
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发表时间：
1964-01-01
影响因子：
4.1
通讯作者：
CHAPPELL, JB
中科院分区：
文献类型：
--
作者：
CHAPPELL, JB
研究了分离线粒体对Ls(+)-异柠檬酸盐的氧化作用。在用二磷酸腺苷和磷酸盐或二硝基苯酚预孵育去除了内源性底物的线粒体中，异柠檬酸不会以显著的速率被氧化，直到以催化量加入苹果酸、草酰乙酸或富马酸。在抑制异柠檬酸生成苹果酸的[β]-氯乙烯氧化二酸或丙二酸存在的情况下，在异柠檬酸被氧化之前必须添加上述二羧酸。随着线粒体内源性底物的消耗，线粒体内烟酰胺核苷酸的广泛减少，与主动呼吸一致，只有当异柠檬酸盐和苹果酸盐一起加入时才能获得。由异柠檬酸脱氢酶还原的烟酰胺腺嘌呤二核苷酸磷酸被烟酰胺核苷酸脱氢酶和苹果酸脱氢酶再氧化。柠檬酸盐的氧化速率是异柠檬酸盐和顺aconitate的40-60%。这可能是由于乌头酸酶活性较低所致。这些发现与线粒体的形态有关。
The oxidation of Ls (+)-isocitrate by isolated mitochondria was in-vestigated. In mitochondria depleted of their endogenous substrates by preincubation with adenosine diphosphate together with phosphate or dinitrophenol, isocitrate was no oxidized at significant rates, until malate, oxaloacetate or fumarate was added in catalytic amounts. In the presence of [beta]-chlorovinylarsenious oxide or malonate, which inhibit the production of malate from isocitrate, the addition of the above-named dicarboxylic acids was necessary before isocitrate was oxidized. With mitochondria that were depleted of their endo-genous substrates, extensive reduction of intramitochondrial nico-tinamide nucleotide, consistent with active respiration, was obtained only when both isocitrate and malate were added together. The nicotinamideadenine dinucleotide phosphate reduced by the isocitrate dehydrogenase is re-oxidized by nicotinamide nucleotide transhydro-genase and malate dehydrogenase. Citrate was oxidized at a rate 40-60% of that of isocitrate and cis-aconitate. It is suggested that this is due to a relatively low aconitase activity. These findings were discussed in relation to the morphology of the mitochondrion.