GLYCEROPHOSPHATEACYLTRANSFERASES AND THEIR FUNCTION IN METABOLISM OF FATTY-ACIDS
GLYCEROPHOSPHATEACYLTRANSFERASES AND THEIR FUNCTION IN METABOLISM OF FATTY-ACIDS
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DOI：
10.1007/bf01731557
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发表时间：
1976-01-01
影响因子：
4.3
通讯作者：
CHRISTIANSEN, R
中科院分区：
文献类型：
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作者：
BREMER, J;BJERVE, KS;CHRISTIANSEN, R
通过对酰基辅酶a：甘油磷酸酰基转移酶（EC 2.3.1.15）和酰基辅酶a:1-酰基甘油磷酸酰基转移酶（EC 2.3.1）的细胞定位、位置特异性和调控特性的不同研究。-)得出以下结论：甘油磷酸酰基转移酶定位于动物细胞的内质网（微粒体）和线粒体外膜。其反应产物为1-酰基甘油磷酸（1-溶血磷脂酸）。线粒体酶显示出对饱和脂肪酸的高度偏好，而微粒体酶的特异性较低（或者微粒体含有1个以上的甘油磷酸酰基转移酶）。1-酰基甘油磷酸酰基转移酶定位于动物细胞的内质网（微粒体）。这种酶的一小部分可能位于线粒体的外膜上。这种酶对不饱和脂肪酸表现出强烈的偏好。微粒体和线粒体二羟基丙酮磷酸酰基转移酶均表现出与相应的甘油磷酸酰基转移酶相似的脂肪酸特异性。二羟基丙酮磷酸和甘油磷酸被相同的酶酰化。肝脏中甘油磷酸酰基转移酶(s)的活性在禁食或脂肪喂养时降低，而在碳水化合物喂养时增加。肉毒碱棕榈基转移酶的活性则完全相反。这些酶在心脏和脂肪组织中没有显示出饮食的变化。在其他条件相同的情况下，当棕榈酰辅酶a浓度降低时，离体线粒体中肉碱酰化率的下降幅度大于甘油磷酸酰化率的下降幅度。在分离的肝细胞（已经失去了大部分的肉碱）中，添加肉碱增加了脂肪酸氧化的速度，降低了甘油三酯的形成速度。甘油和果糖降低了脂肪酸氧化的速率，可能是通过降低细胞中酰基辅酶a和酰基肉碱的水平。甘油磷酸酰基转移酶和肉碱棕榈酰基转移酶的相对活性可能影响脂肪酸在细胞中的命运。
From different studies on the cellular localization, positional specificity and regulatory properties of acyl-CoA: glycerophosphate acyltransferase (EC 2.3.1.15) and acyl-CoA:1-acylglycerophosphate acyltransferase (EC 2.3.1.-) the following conclusions were drawn: The glycerophosphate acyltransferase was localized in the endoplasmatic reticulum (microsomes) and in the outer membrane of the mitochondria of the animal cell. Its reaction product was 1-acylglycerophosphate (1-lysophosphatidic acid). The mitochondrial enzyme showed a high perference for saturated fatty acids while the microsomal enzyme was less specific (alternatively the microsomes contained more than 1 glycerophosphate acyltransferase). The 1-acylglycerophosphate acyltransferase was localized in the endoplasmatic reticulum (microsomes) in the animal cell. Possibly a minor fraction of this enzyme was localized to the outer membrane of the mitochondria. This enzyme showed a strong preference for unsaturated fatty acids. Both the microsomal and the mitochondrial dihydroxyacetonephosphate acyltransferase showed similar fatty acid specificity as the corresponding glycerophosphate acyltransferases. Dihydroxyacetonephosphate and glycerophosphate were acylated by the same enzymes. The activity of the glycerophosphate acyltransferase(s) in the liver decreased in fasting or fat feeding and increased upon feeding of carbohydrate. The activity of carnitine palmityltransferase varied exactly oppositely. These enzymes did not show dietary variations in heart and adipose tissue. Under otherwise identical conditions, the rate of carnitine acylation in isolated mitochondria decreased more than the rate of glycerophosphate acylation when the concentration of palmityl-CoA was reduced. In isolated liver cells (which had lost most of their carnitine) addition of carnitine increased the rate of fatty acid oxidation and decreased the rate of triglyceride formation. Glycerol and fructose lowered the rate of fatty acid oxidation, probably by lowering the levels of acyl-CoA and acyl-carnitine in the cells. The relative activities of glycerophosphate acyltransferase and carnitine palmityltransferase probably influence the fate of fatty acids in the cell.