Retention of lipolytic products in chylomicrons incubated with lipoprotein lipase: electron microscope study.
Retention of lipolytic products in chylomicrons incubated with lipoprotein lipase: electron microscope study.
复制标题
用脂蛋白脂肪酶孵育的乳糜微粒中脂肪分解产物的保留：电子显微镜研究。
作者：
E. Blanchette‐Mackie;R. Scow
在大鼠乳糜微粒与纯化的牛温和脂蛋白脂肪酶在pH8.1孵育的早期影响，在体外乳糜微粒的结构进行了研究。限制加入孵育培养基中的白蛋白量，以使脂解过程中形成的游离脂肪酸（FFA）和偏甘油酯在乳糜微粒中蓄积。在脂肪分解乳糜微粒中可视化的结构被发现在制备用于显微镜的标本期间受pH影响，无论是用OsO4固定并切片，还是用磷钨酸钠染色并作为整体进行检查。在pH 8.1和7.4下处理的脂解乳糜微粒的甘油三酯核心中存在圆形水性空间。有时候，这些空隙中含有嗜锇物质的聚集体和双层薄片的螺旋。在pH 5.5下处理的乳糜微粒中，空间被具有40 A周期性的层状结构所取代，并且在pH 3.0下空间和层状结构都不存在。这些结果表明，这些空间内衬的脂质单层，形成双层层在一定条件下。它的结论是，单层内衬的水的空间是由脂肪分解产物，FFA和偏甘油酯，在核心甘油三酯和水之间的界面平面的积累和运动所产生的乳糜微粒表面膜的向内延伸。
Early effects of lipolysis on the structure of chylomicrons in vitro were studied in rat chylomicrons incubated with purified bovine mild lipoprotein lipase at pH 8.1. The amount of the albumin added to the incubation medium was limited so that free fatty acids (FFA) and partial glycerides formed during lipolysis would accumulate in the chylomicrons. The structures visualized in lipolyzed chylomicrons was found to be affected by pH during preparation of specimens for microscopy, whether fixed with OsO4 and sectioned, or stained with sodium phosphotungstate and examined as whole mounts. Circular aqueous spaces were present in the triglyceride core of lipolyzed chylomicrons processed at pH 8.1 and 7.4. Sometimes the spaces contained aggregates of osmiophilic material and whorls of bilayered lamellae. The spaces were replaced by lamellar structures having a periodicity of 40 A, in chylomicrons processed at pH 5.5, and the spaces and lamellae were both absent at pH 3.0. The findings indicate that these spaces were lined by a lipid monolayer which formed bilayered lamellae under certain conditions. It is concluded that the monolayer lining the aqueous spaces is an inward extension of the chylomicron surface film produced by the accumulation and movement of lipolytic products, FFA and partial glycerides, in the interfacial plane between core triglyceride and water.