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纯化的GPI-PLD是分子量为100kD的单肽链,而血清经凝胶过滤时,该酶为500kD。了解酶分子天然状态下的性质,有助于认识其生理功能。采用凝胶过滤、疏水柱层析及超速离心分离并测定该酶活性及磷脂、甘油三酯和胆固醇的浓度,结果说明,GPI-PLD在血清中不是以肽的多聚体形式存在,而可能是与血脂结合,形成蛋白与脂的复合物,经超速离心后存在于HDL的密度区内。但该复合物与富含Apo-A1的HDL亚类是相互独立存在的,并且能结合于硫酸肝素亲和层析柱上,表现出与另一种脱辅基脂蛋白Apo-E类似的层析性质。
The purified GPI-PLD was a single peptide chain with a molecular weight of 100 kD, whereas the serum was gel filtered and the enzyme was 500 kD. Understanding the nature of the enzyme molecule in its natural state helps to understand its physiological function. Gel filtration, hydrophobic column chromatography and ultracentrifugation were performed to determine the enzyme activity and the concentrations of phospholipids, triglycerides and cholesterol. The results indicated that GPI-PLD did not exist in the serum as a multimeric form of the peptide, Is combined with blood lipids, the formation of protein and lipid complexes, after ultracentrifugation in the HDL density zone. This complex, however, is present independently of the Apo-A1-rich HDL subclass and binds to heparin sulfate affinity columns and displays a similar layer to another apolipoprotein Apo-E Analysis of the nature.