SCANU A, PAGE I H
J Exp Med. 1959 Mar 1;109(3):239-56. doi: 10.1084/jem.109.3.239.
Chylomicrons were separated by low and high speed ultracentrifugation from lipemic sera of human subjects in the absorptive phase. The final chylomicron preparation was free from other serum components and contained a small constant amount of protein, approximately 2 per cent of the chylomicron fraction. Electrophoresis, immunochemical analysis, and absorption experiments identified the protein component as derived from a mixture of beta and alpha(1) serum lipoproteins. Large aliquots of an emulsion of serum freed of chylomicrons and coconut oil were incubated at 37 degrees C. for 2 hours and ultracentrifuged as in the preparation of chylomicrons. The fat particles now showed the presence of minute amounts of beta and alpha(1) serum lipoproteins in almost the same proportion as found in chylomicrons. "Finger prints" of delipidized samples of chylomicrons and particles from serum-coconut oil emulsion gave similar, although not identical patterns. The data on "clearing factor" activity corroborated the finding that serum alpha(1) lipoproteins are contained in chylomicrons and particles from serum-coconut oil emulsion. These two lipide particles, partially delipidized, were both able to activate a "clearing factor" system in vitro, a property exhibited only by intact or partially delipidized alpha(1) serum lipoproteins. Clearing activity was satisfactorily determined by using an emulsion of coconut oil mixed in agar as a substrate to give an opaque gel, in which the diffusing enzyme showed its activity by areas of clearing. The results obtained by this technique were in agreement with those based on fall in optical density and non-esterified fatty acid production. Chemical analysis of serum chylomicrons showed a concentration of cholesterol and phospholipides higher than could be accounted for by the attached beta and alpha(1) serum lipoproteins. On the basis of these results the assumption is made that in the blood stream small amounts of serum lipoproteins, by a process of adsorption, form a complex with the absorbed triglycerides, cholesterol, and phospholipides, to produce chylomicrons.
在吸收期，通过低速和高速超速离心从人类受试者的脂血血清中分离出乳糜微粒。最终的乳糜微粒制剂不含其他血清成分，并含有少量恒定的蛋白质，约占乳糜微粒部分的2%。电泳、免疫化学分析和吸收实验确定该蛋白质成分源自β和α1血清脂蛋白的混合物。将大量不含乳糜微粒的血清与椰子油的乳剂在37℃孵育2小时，并像制备乳糜微粒一样进行超速离心。现在脂肪颗粒显示存在微量的β和α1血清脂蛋白，其比例几乎与乳糜微粒中的相同。乳糜微粒和血清 - 椰子油乳剂颗粒的脱脂样品的“指纹图谱”给出了相似但不完全相同的模式。关于“清除因子”活性的数据证实了乳糜微粒和血清 - 椰子油乳剂颗粒中含有血清α1脂蛋白这一发现。这两种部分脱脂的脂质颗粒在体外都能够激活“清除因子”系统，这是完整或部分脱脂的α1血清脂蛋白才具有的特性。通过使用混合在琼脂中的椰子油乳剂作为底物来产生不透明凝胶，其中扩散酶通过清除区域显示其活性，从而令人满意地测定清除活性。通过该技术获得的结果与基于光密度下降和非酯化脂肪酸产生的结果一致。血清乳糜微粒的化学分析表明，胆固醇和磷脂的浓度高于附着的β和α1血清脂蛋白所能解释的浓度。基于这些结果，假设在血流中少量血清脂蛋白通过吸附过程与吸收的甘油三酯、胆固醇和磷脂形成复合物，从而产生乳糜微粒。
