灵长类动物组织中支链α-酮酸脱氢酶的分布
Distribution of branched-chain alpha-keto acid dehydrogenases in primate tissues.
作者信息
Khatra B S, Chawla R K, Sewell C W, Rudman D
出版信息
J Clin Invest. 1977 Mar;59(3):558-64. doi: 10.1172/JCI108671.
The specific activity of the branched-chain alpha-keto acid (BCKA) dehydrogenases was measured in normal tissues of the rat, monkey, and man, and in cirrhotic human liver. In the rat, specific activity of the dehydrogenases in liver, kidney, and muscle averaged 33, 26, and 0.4 U/g wet tissue, respectively; proportion of the body's content of the enzyme located in these three organs was 70, 12, and 10%. In the monkey, specific activities in liver and kidney were only one-half to one-third as great as in the rat, whereas activity in muscle was the same; the monkey's body content of dehydrogenase was distributed 50% in liver, 13% in kidney, and 20% in muscle. In man, specific activities in liver and kidney were only 1/15th to 1/25th as great as in the rat, but activity in skeletal muscle was the same. Distribution of the dehydrogenases in man was 30% in liver, 2% in kidneys, and 60% in muscle. In six patients with alcoholic cirrhosis, specific activity of the dehydrogenase in liver was reduced to 20-50% of normal (average, 32%). This reduction may alter the efficiency of BCKA as substitutes for branched-chain amino acids when BCKA are administered orally, but will have little influence on efficiency when they are given intravenously.
测定了大鼠、猴和人的正常组织以及肝硬化人肝脏中支链α-酮酸（BCKA）脱氢酶的比活性。在大鼠中，肝脏、肾脏和肌肉中脱氢酶的比活性分别平均为33、26和0.4 U/g湿组织；该酶在大鼠体内这三个器官中的含量比例分别为70%、12%和10%。在猴中，肝脏和肾脏中的比活性仅为大鼠的二分之一到三分之一，而肌肉中的活性相同；猴体内脱氢酶的含量分布为肝脏50%、肾脏13%、肌肉20%。在人中，肝脏和肾脏中的比活性仅为大鼠的十五分之一到二十五分之一，但骨骼肌中的活性相同。脱氢酶在人身体中的分布为肝脏30%、肾脏2%、肌肉60%。在6例酒精性肝硬化患者中，肝脏中脱氢酶的比活性降至正常的20% - 50%（平均为32%）。这种降低可能会改变口服BCKA替代支链氨基酸的效率，但静脉注射时对效率影响不大。
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