DIFFERENTIAL ENERGETIC METABOLISM DURING TRYPANOSOMA-CRUZI DIFFERENTIATION .1. CITRATE SYNTHASE, NADP-ISOCITRATE DEHYDROGENASE, AND SUCCINATE-DEHYDROGENASE
DIFFERENTIAL ENERGETIC METABOLISM DURING TRYPANOSOMA-CRUZI DIFFERENTIATION .1. CITRATE SYNTHASE, NADP-ISOCITRATE DEHYDROGENASE, AND SUCCINATE-DEHYDROGENASE
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DOI：
10.1016/0003-9861(88)90030-6
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发表时间：
1988-11-15
影响因子：
3.9
通讯作者：
LUPIANEZ, JA
中科院分区：
文献类型：
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作者：
ADROHER, FJ;OSUNA, A;LUPIANEZ, JA
线粒体的活动！研究了柠檬酸合成酶(柠檬酸草酰乙酸酶，EC 4.1.3.7)、异柠檬酸脱氢酶(苏式-DS-异柠檬酸：NADP+氧化还原酶(脱羧酶，EC 1.1.1.42)和琥珀酸脱氢酶(琥珀酸：FAD氧化还原酶，EC 1.3.99.1)，以及它们在昆虫媒介期、表鞭毛虫和感染性偏环类锥虫两种发育形态中的动力学行为。这项工作的结果清楚地表明，半环形式的线粒体具有更高的新陈代谢，这表现在半环柠檬酸合成酶、异柠檬酸脱氢酶和琥珀酸脱氢酶的活性显著增强。在上胚芽中，不同浓度的草酸乙酯和乙酰辅酶A对柠檬酸合成酶的比活分别为24.6mU/mg和26.6mU/mg蛋白质，米氏常数分别为7.88和6.84μM。该酶的动力学参数为：草乙酸酯的比活力为228.4 mU/mg，Kmof为3.18μm；乙酰辅酶A的比活力为248.5 mU/mg，Kmof为2.75μm。异柠檬酸脱氢酶比活力分别为110.2和210.3 mU/mg，表观Km分别为47.9mU/mg和12.5mU/μ。没有发现任何形式的NAD依赖的同工酶活性。弯曲性分化。颗粒琥珀酸脱氢酶对上鞭毛体和准环体鞭毛虫的比活力分别为8.2 mU/mg和39.1 mU/mg，Km(0.46和0.48 mM)没有显著变化。细胞的作用和分子机制可能发生在这一重大转变线粒体代谢在Thet。此外，还讨论了克鲁兹分化问题。
The activities of the mitochondria! enzymes citrate synthase (citrate oxaloacetatelyase, EC 4.1.3.7), NADP-linked isocitrate dehydrogenase (threo-ds-isocitrate:NADP+oxidoreductase (decarboxylating), EC 1.1.1.42), and succinate dehydrogenase (succinate: FAD oxidoreductase, EC 1.3.99.1) as well as their kinetic behavior in the two developmental forms ofTrypanosoma cruziat insect vector stage, epimastigotes and infective metacyclic trypomastigotes, were studied. The results presented in this work clearly demonstrate a higher mitochondrial metabolism in the metacyclic forms as is shown by the extraordinary enhanced activities of metacyclic citrate synthase, isocitrate dehydrogenase, and succinate dehydrogenase. In epimastigotes, the specific activities of citrate synthase at variable concentrations of oxalacetate and acetyl-CoA were 24.6 and 26.6 mU/mg of protein, respectively, and the Michaelis constants were 7.88 and 6.84 μM for both substrates. The metacyclic enzyme exhibited the following kinetic parameters: a specific activity of 228.4 mU/mg andKmof 3.18 μmfor oxalacetate and 248.5 mU/mg and 2.75 μm, respectively, for acetyl-CoA. NADP-linked isocitrate dehydrogenase specific activities for epimastigotes and metacyclics were 110.2 and 210.3 mU/mg, whereas the apparentKm's were 47.9 and 12.5 μm, respectively. No activity for the NAD-dependent isozyme was found in any form ofT. cruzidifferentiation. The particulated succinate dehydrogenase showed specific activities of 8.2 and 39.1 mU/mg for epimastigotes and metacyclic trypomastigotes, respectively, although no significant changes in theKm(0.46 and 0.48 mm) were found. The cellular role and the molecular mechanism that probably take place during this significant shift in the mitochondrial metabolism during theT. cruzidifferentiation have been discussed.