MITOCHONDRIAL TRIFUNCTIONAL PROTEIN-DEFICIENCY - CATALYTIC HETEROGENEITY OF THE MUTANT ENZYME IN 2 PATIENTS
MITOCHONDRIAL TRIFUNCTIONAL PROTEIN-DEFICIENCY - CATALYTIC HETEROGENEITY OF THE MUTANT ENZYME IN 2 PATIENTS
复制标题
DOI：
10.1172/jci117158
复制
发表时间：
1994-04-01
影响因子：
15.9
通讯作者：
HASHIMOTO, T
中科院分区：
文献类型：
--
作者：
KAMIJO, T;WANDERS, RJA;HASHIMOTO, T
我们研究了长链3-羟酰辅酶A脱氢酶缺乏症患者培养的皮肤成纤维细胞中的酶蛋白和人三功能蛋白的生物合成，所述三功能蛋白具有烯酰辅酶A水合酶、3-羟酰辅酶A脱氢酶和3-酮酰辅酶A硫解酶活性。获得了以下结果。(a)在来自患者1的细胞中，免疫印迹分析和脉冲追踪实验表明，三功能蛋白质的含量小于对照细胞中的含量的10%，这是由于线粒体中新合成的蛋白质的非常快速的降解。三功能蛋白的减少与烯酰辅酶A水合酶，3-羟酰辅酶A脱氢酶，3-酮酰辅酶A硫解酶的活性降低，当使用中链至长链底物测量。(b)在来自患者2的细胞中，新合成的三功能蛋白质的降解速率比对照细胞中的降解速率快，导致三功能蛋白质达到对照水平的60%。中链至长链底物的3-羟酰辅酶A脱氢酶活性急剧下降，其他两种酶的活性变化较小。这些数据表明来自患者2的细胞中三功能蛋白质的细微异常。两者合计，所获得的结果表明，在这两个患者中，长链3-羟酰辅酶A脱氢酶缺乏症是由三功能蛋白质的异常引起的，即使在这两个患者中存在异质性。
We examined the enzyme protein and biosynthesis of human trifunctional protein harboring enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase, and 3-ketoacyl-CoA thiolase activity in cultured skin fibroblasts from two patients with long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency. The following results were obtained. (a) In cells from patient 1, immunoblot analysis and pulse-chase experiments indicated that the content of trifunctional protein was < 10% of that in control cells, due to a very rapid degradation of protein newly synthesized in the mitochondria. The diminution of trifunctional protein was associated with a decreased activity of enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase, and 3-ketoacyl-CoA thiolase, when measured using medium-chain to long-chain substrates. (b) In cells from patient 2, the rate of degradation of newly synthesized trifunctional protein was faster than that in control cells, giving rise to a trifunctional protein amounting to 60% of the control levels. The 3-hydroxyacyl-CoA dehydrogenase activity with medium-chain to long-chain substrates was decreased drastically, with minor changes in activities of the two other enzymes. These data suggest a subtle abnormality of trifunctional protein in cells from patient 2. Taken together, the results obtained show that in both patients, long-chain 3-hydroxyacyl-CoA dehydrogenase deficiency is caused by an abnormality in the trifunctional protein, even though there is a heterogeneity in both patients.