Sato A, Nagai M, Tagami A, Natori Y, Okada M
Department of Nutritional Chemistry, School of Medicine, University of Tokushima, Japan.
J Nutr Sci Vitaminol (Tokyo). 1991 Aug;37(4):419-24. doi: 10.3177/jnsv.37.419.
Highly purified lysosomes were isolated from the livers of control and pyridoxine-deficient rats. The calculation of the lysosomal protein contents indicated that the livers of both groups of rats contain virtually the same amounts of the lysosomal proteins (12.0 and 13.0 mg lysosomal proteins/g liver proteins for the control and pyridoxine-deficient rats, respectively). The immunoblotting of the lysosomal proteins with anti-cytosolic aspartate aminotransferase (cAspAT) showed 46 kDa band, corresponding to the subunit molecular weight of cAspAT, as well as the bands representing degradative intermediates of cAspAT. The relative amounts of the immuno-reactive substances were estimated by scanning the immuno-stained bands and measuring the densitometric tracings. It was found that the lysosomes in the pyridoxine-deficient rat liver contain almost twice as much cAspAT and its degradative intermediates as those in the control rat liver. On the basis of these observations, it was concluded that the increased rate of degradation of cAspAT in the liver of the pyridoxine-deficient rats is brought about by the increased rate of sequestration of cAspAT into lysosomes.
从对照大鼠和缺乏维生素B6的大鼠肝脏中分离出高度纯化的溶酶体。溶酶体蛋白质含量的计算表明，两组大鼠肝脏中溶酶体蛋白质的含量几乎相同（对照大鼠和缺乏维生素B6的大鼠肝脏中溶酶体蛋白质分别为12.0和13.0毫克/克肝脏蛋白质）。用抗胞质天冬氨酸转氨酶（cAspAT）对溶酶体蛋白质进行免疫印迹分析，显示出46 kDa的条带，对应于cAspAT的亚基分子量，以及代表cAspAT降解中间体的条带。通过扫描免疫染色条带并测量光密度扫描图来估计免疫反应性物质的相对含量。结果发现，缺乏维生素B6的大鼠肝脏中的溶酶体所含的cAspAT及其降解中间体几乎是对照大鼠肝脏中的两倍。基于这些观察结果，得出结论：缺乏维生素B6的大鼠肝脏中cAspAT降解速率的增加是由于cAspAT被溶酶体隔离的速率增加所致。
