Enzymes of L-(+)-3-hydroxybutyrate metabolism in the rat.
Enzymes of L-(+)-3-hydroxybutyrate metabolism in the rat.
复制标题
大鼠L-( )-3-羟基丁酸代谢酶。
DOI：
10.1016/0003-9861(80)90087-9
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发表时间：
1980
影响因子：
3.9
通讯作者：
Pinar T. Ozand
中科院分区：
文献类型：
--
作者：
W. Reed;Pinar T. Ozand
在大鼠的各种组织中寻找产生和利用1-（+）-3-羟基丁酸所需的三种酶。检查的所有组织均含有大量（1号）1-（+）-3-羟基丁酰CoA脱氢酶（EC 1.1.1.35）。（No.2）1-（+）-3-羟基丁酰辅酶A脱酰酶（EC 3.1.2）的比活性在肝脏中最高（3.8 mU/mg，在线粒体基质中（1 U = 1 μmol/min））。大脑、心脏和骨骼肌含有< 20%的这种活性。在DEAE-纤维素上的肝线粒体“基质”制剂的色谱将脱酰酶分解成两个峰。峰I比1-（+）-3-羟基丁酸CoA更有效地水解2-或3-碳酰基CoA酯，而峰II活性使用1-（+）-3-羟基丁酰CoA最高。峰II脱酰酶与1-（+）-3-羟基丁酰辅酶A的Km（app）为19 μm。用山梨酸酯（山梨酰CoA连接酶）或1-（+）-3-羟基丁酸酯（1-（+）-3-羟基丁酰CoA连接酶）测定酰基CoA合成酶（EC 6.2.1.2）（No.3）。1-（+）-3-羟基丁酰CoA连接酶的最高比活性与脑线粒体相关（8.3 mU/mg）。在大鼠肝脏线粒体的“基质”部分中，这两种酰基CoA合成酶的活性通过色谱法及其在不同pH值下的稳定性来区分。心脏和骨骼肌线粒体含有<10%的肝脏活性的两种连接酶。这些数据表明肝脏是l-（+）-3-羟基丁酸盐产生的部位。
The three enzymes required for the production and utilization ofl-(+)-3-hydroxybutyrate were sought in various tissues of the rat. All tissues examined contained substantial amounts of (No. 1)l-(+)-3-hydroxybutyryl CoA dehydrogenase (EC 1.1.1.35). The specific activity of (No. 2)l-(+)-3-hydroxybutyryl CoA deacylase (EC 3.1.2) was highest in liver (3.8 mU/mg in mitochondrial matrix (1 U = 1 μmol/min). Brain, heart, and skeletal muscle contained < 20% of this activity. The chromatography of liver mitochondrial “matrix” preparations on DEAE-cellulose resolved the deacylase into two peaks. Peak I hydrolyzed 2- or 3- carbon acylCoA esters more efficiently thanl-(+)-3-hydroxybutyrate CoA, while Peak II activity was highest usingl-(+)-3-hydroxybutyryl CoA. TheKm(app)for Peak II deacylase withl-(+)-3-hydroxybutyryl CoA was 19 μm. Acyl CoA synthetase (EC 6.2.1.2) (No. 3) was assayed with sorbate (sorboyl CoA ligase) orl-(+)-3-hydroxybutyrate (l-(+)-3-hydroxybutyryl CoA ligase). The highest specific activity forl-(+)-3-hydroxybutyryl CoA ligase was associated with brain mitochondria (8.3 mU/mg). In the “matrix” fraction of rat liver mitochondria the activities of these two acyl CoA synthetases were distinguished chromatographically and by their stability at various pH values. Heart and skeletal muscle mitochondria contained <10% of the liver activities of both ligases. These data implicate the liver as a site ofl-(+)-3-hydroxybutyrate production.