Musliner T A, McVicker K M, Iosefa J F, Krauss R M
Biochim Biophys Acta. 1987 Jun 2;919(2):97-110. doi: 10.1016/0005-2760(87)90196-2.
In the course of lipolysis, surface lipid products may accumulate on very-low-density lipoproteins (VLDL). To investigate potential lipoprotein interactions mediated by such products, radiolabeled low-density lipoproteins (LDL) were incubated with VLDL and bovine milk lipoprotein lipase in the presence of limited free fatty acid acceptor. With partial VLDL degradation, association of radiolabeled LDL with VLDL remnants or larger aggregates of VLDL density was demonstrated by gradient gel electrophoresis, agarose chromatography, and density gradient ultracentrifugation. VLDL-LDL complex formation was also observed in incubations with lipid extracts from lipolyzed VLDL or with purified palmitic acid in the absence of lipolysis. Complex formation was inhibited by addition of increasing amounts of albumin as free fatty acid acceptor, but could be detected at molar ratios of free fatty acids/albumin that occur in vivo. Composition analysis of LDL reisolated following incubation with VLDL and lipase under conditions favoring partial complex formation revealed enrichment in glycerides and depletion of cholesterol. We conclude that lipolysis products can promote the formation of stable complexes of LDL and VLDL, and that physical interactions of this nature may play a role in the transfer of lipids and apolipoproteins between lipoprotein particles.
在脂肪分解过程中，表面脂质产物可能会在极低密度脂蛋白（VLDL）上积累。为了研究由此类产物介导的潜在脂蛋白相互作用，在有限游离脂肪酸受体存在的情况下，将放射性标记的低密度脂蛋白（LDL）与VLDL及牛乳脂蛋白脂肪酶一起孵育。随着VLDL的部分降解，通过梯度凝胶电泳、琼脂糖色谱法和密度梯度超速离心法证明了放射性标记的LDL与VLDL残余物或密度更大的VLDL聚集体相关联。在与脂解VLDL的脂质提取物或在无脂肪分解情况下与纯化的棕榈酸孵育时，也观察到了VLDL-LDL复合物的形成。随着游离脂肪酸受体白蛋白添加量的增加，复合物形成受到抑制，但在体内出现的游离脂肪酸/白蛋白摩尔比下仍可检测到。在有利于部分复合物形成的条件下，将LDL与VLDL及脂肪酶一起孵育后重新分离得到的LDL的成分分析显示甘油酯富集而胆固醇减少。我们得出结论，脂肪分解产物可促进LDL和VLDL稳定复合物的形成，并且这种性质的物理相互作用可能在脂蛋白颗粒之间的脂质和载脂蛋白转移中起作用。
