Identification, separation, and characterization of acyl-coenzyme A dehydrogenases involved in mitochondrial β-oxidation in higher plants
Identification, separation, and characterization of acyl-coenzyme A dehydrogenases involved in mitochondrial β-oxidation in higher plants
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DOI：
10.1104/pp.119.4.1305
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发表时间：
1999-04-01
期刊：
影响因子：
7.4
通讯作者：
Couée, I
中科院分区：
文献类型：
--
作者：
Bode, K;Hooks, MA;Couée, I
在高等植物中，除了特征明确的过氧化物酶体系统外，线粒体中还存在另外的β-氧化系统，这一点经常被认为是有争议的。线粒体中β-氧化活性的明确证明应依赖于线粒体β-氧化特异性酶的鉴定。1.3.99.2从玉米（Zea mays L.）以早萌向日葵（Helianthus annuus L.）种子，使用作为酶测定的2，6-二氯酚靛酚的还原，与吩嗪硫酸甲酯作为中间电子载体。亚细胞分离表明，这种ACAD活性与线粒体组分。线粒体中ACAD活性和过氧化物酶体中酰基辅酶A氧化酶活性的比较显示底物特异性的差异。向日葵种子的胚轴被用作纯化ACADs的起始材料。两种不同的ACADs，分别具有中链和长链底物特异性，通过它们的色谱行为分离，这与哺乳动物的ACADs相似。这些ACADs的表征进行了讨论，在cDNA序列分析项目中，并与线粒体P-氧化在高等植物中的潜在作用，以确定相应的ACADs的表达序列标签。
The existence in higher plants of an additional beta-oxidation system in mitochondria, besides the well-characterized peroxisomal system, is often considered controversial. Unequivocal demonstration of beta-oxidation activity in mitochondria should rely on identification of the enzymes specific to mitochondrial beta-oxidation. Acyl-coenzyme A dehydrogenase (ACAD) (EC 1.3.99.2,3) activity was detected in purified mitochondria from maize (Zea mays L.) root tips and from embryonic axes of early-germinating sunflower (Helianthus annuus L.) seeds, using as the enzyme assay the reduction of 2,6-dichlorophenolindophenol, with phenazine methosulfate as the intermediate electron carrier. Subcellular fractionation showed that this ACAD activity was associated with mitochondrial fractions. Comparison of ACAD activity in mitochondria and acylcoenzyme A oxidase activity in peroxisomes showed differences of substrate specificities. Embryonic axes of sunflower seeds were used as starting material for the purification of ACADs. Two distinct ACADs, with medium-chain and long-chain substrate specificities, respectively, were separated by their chromatographic behavior, which was similar to that of mammalian ACADs. The characterization of these ACADs is discussed in relation to the identification of expressed sequenced tags corresponding to ACADs in cDNA sequence analysis projects and with the potential roles of mitochondrial P-oxidation in higher plants.