PARTIAL-PURIFICATION AND PROPERTIES OF HUMAN-BRAIN ALDEHYDE DEHYDROGENASES
PARTIAL-PURIFICATION AND PROPERTIES OF HUMAN-BRAIN ALDEHYDE DEHYDROGENASES
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DOI：
10.1111/j.1471-4159.1985.tb10550.x
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发表时间：
1985-01-01
影响因子：
4.7
通讯作者：
LITTLE, R
中科院分区：
文献类型：
--
作者：
MARING, JA;DEITRICH, RA;LITTLE, R
以乙醛和生物醛为底物，研究了乙醛脱氢酶活性在人脑组织中的亚细胞分布。用10 μ M乙醛作为底物，在线粒体部分中发现超过50%的总活性，38%与细胞质有关。然而，用4 μ M 3，4-二羟基苯乙醛和10 μ M吲哚乙醛作为底物，在可溶性部分中发现总活性的40-50%，线粒体部分仅占总活性的15-30%。这些数据表明，存在不同的醛脱氢酶同工酶在不同的车厢。因此，对线粒体和细胞质部分进行盐分级和离子交换层析，以进一步纯化两种部分中存在的同工酶。部分纯化的同工酶的动力学数据揭示了线粒体和胞质溶胶中存在低Km同工酶，乙醛的Km值分别为1.7 μ M和10.2 μ M。然而，胞浆同工酶对生物源醛的Km值较低。在pH 7.4的磷酸盐缓冲液中，Mg ~（2+）和Ca ~（2+）均能激活两种同工酶。此外，高Km同工酶被发现在线粒体和微粒体。
Acetaldehyde and biogenic aldehydes were used as substrates to investigate the subcellular distribution of aldehyde dehydrogenase activity in autopsied human brain. With 10 .mu.M acetaldehyde as substrate, over 50% of the total activity was found in the mitochondrial fraction and 38% was associated with cytosol. However, with 4 .mu.M 3,4-dihydroxyphenylacetaldehyde and 10 .mu.M indoleacetaldehyde as substrates, 40-50% of the total activity was found in the soluble fraction, the mitochondrial fraction accounting for only 15-30% of the total activity. These data suggested the presence of distinct aldehyde dehydrogenase isozymes in the different compartments. The mitochondrial and cytosolic fractions were therefore, subjected to salt fractionation and ion exchange chromatography to purify further the isozymes present in both fractions. The kinetic data on the partially purified isozymes revealed the presence of a low Km isozyme in both the mitochondria and the cytosol, with Km values for acetaldehyde of 1.7 .mu.M and 10.2 .mu.M, respectively. However, the cytosolic isozyme exhibited lower Km values for the biogenic aldehydes. Both isozymes were activated by Mg2+ and Ca2+ in phosphate buffers (pH 7.4). Also, high Km isozymes were found in the mitochondria and in the microsomes.