1-Alkyl-sn-glycero-3-phosphate: acyl-CoA acyltransferase in rat brain microsomes.
1-Alkyl-sn-glycero-3-phosphate: acyl-CoA acyltransferase in rat brain microsomes.
复制标题
1-烷基-sn-甘油-3-磷酸：大鼠脑微粒体中的酰基辅酶A酰基转移酶。
DOI：
10.1016/s0021-9258(17)40600-4
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发表时间：
1977
期刊：
影响因子：
--
通讯作者：
A. Hajra
中科院分区：
文献类型：
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作者：
P. Fleming;A. Hajra
1-烷基-sn-甘油-3-磷酸：酰基-CoA酰基转移酶活性在6个大鼠组织中发现：心脏、脾脏、脑、肾脏、肝脏和肺。大鼠脑中的酶在微粒体组分中表现出最高的比活性，并对其性质进行了详细研究。Triton X-100和牛血清白蛋白被发现刺激酶的活性。结果发现，Triton X-100影响的酰基转移酶活性差异取决于酰基辅酶A供体。白蛋白逆转了高浓度1-烷基-sn-甘油-3-磷酸引起的抑制作用。该酶被证明是立体特异性酰化的烷基甘油磷酸底物。只有1-烷基-sn-甘油-3-磷酸异构体，而不是其他光学对映异构体，是积极的脑酰基转移酶。证据表明，这种酶是不同的1-酰基-sn-甘油-3-磷酸：酰基辅酶A酰基转移酶。对不同酰基-CoA种类（16：0、18：0、18：2、20：4、22：4、22：6）的脑酰基转移酶活性的特异性的研究显示了依赖于烷基甘油磷酸浓度的选择性。在低1-烷基-SN-甘油-3-磷酸浓度下，酶选择多不饱和酰基-CoA物质而不是饱和物质。通过在孵育混合物中用NADPH原位酶促还原烷基二羟基丙酮磷酸，实现向酰基转移酶提供低但连续量的1-烷基-sn-甘油-3-磷酸。测定了大鼠脑微粒体中含醚磷酸甘油酯的酰基组成以及游离脂肪酸组成。烯基酰基甘油磷酸乙醇胺含有高百分比的22：6酯，烯基酰基甘油磷酸胆碱含有大量的16：0酯。比较1-烷基-sn-甘油-3-磷酸酰基转移酶和醚/甘油酯酰基组成的酰基CoA特异性表明，该酰基转移酶可以部分地确定醚脂质中酰基的组成。
1-Alkyl-sn-glycero-3-phosphate:acyl-CoA acyltransferase activity was found in six rat tissues: heart, spleen, brain, kidney, liver, and lung. The enzyme in rat brain showed highest specific activity in the microsomal fraction and its properties were studied in detail. Triton X-100 and bovine serum albumin were found to stimulate the activity of the enzyme. It was found that Triton X-100 affects the acyltransferase activity differentially depending on the acyl-CoA donor. Albumin reversed the inhibition caused by a high concentration of 1-alkyl-sn-glycero-3-phosphate. The enzyme was shown to be stereospecific in acylating the alkylglycerophosphate substrate. Only the 1-alkyl-sn-glycero-3-phosphate isomer, not the other optical enantiomer, was active with brain acyltransferase. Evidence is presented to show that this enzyme is different from 1-acyl-sn-glycero-3-phosphate:acyl-CoA acyltransferase. Investigations of the specificity of the brain acyltransferase activity for different acyl-CoA species (16:0, 18:0, 18:2, 20:4, 22:4, 22:6) showed a selectivity which was dependent on the alkylglycerophosphate concentration. At low 1-alkyl-sn-glycero-3-phosphate concentration the enzyme selected polyunsaturated acyl-CoA species over saturated species. Providing a low but continuous amount of 1-alkyl-sn-glycero-3-phosphate to the acyltransferase was accomplished by the in situ enzymatic reduction of alkyldihydroxyacetone phosphate with NADPH in the incubation mixtures. The acyl composition of ether-containing phosphoglycerides in rat brain microsomes, as well as the free fatty acid composition, was determined. Alkenylacylglycerophosphorylethanolamine contains a high percentage of 22:6 ester, and alkenylacylglycerophosphorylcholine contains a large amount of 16:0 ester. Comparison of the acyl-CoA specificity of 1-alkyl-sn-glycero-3-phosphate acyltransferase and ether/glycerolipid acyl composition suggests that this acyltransferase could partially determine the composition of acyl groups in ether lipids.