Jadot M, Wattiaux-De Coninck S, Wattiaux R
Eur J Biochem. 1985 Sep 16;151(3):485-8. doi: 10.1111/j.1432-1033.1985.tb09127.x.
The intracellular localization of invertase endocytosed by rat liver was investigated by analytical centrifugation in sucrose and Percoll gradients of mitochondrial fractions originating from rats killed 15 h after injection. After isopycnic centrifugation in a sucrose gradient, invertase is located in higher density zones than acid hydrolases. The difference between the distribution of invertase and that of acid hydrolases increases with the amount of invertase injected. When the invertase dose is sufficiently high, a change of lysosomal enzyme distribution is clearly visible. It consists in the shift of a proportion of these enzymes to higher density regions where invertase is located. The proportion of hydrolase activity affected by invertase is different for each enzyme measured; it is the least pronounced for acid phosphatase, and most for acid deoxyribonuclease and arylsulfatase. A pretreatment of the rat with Triton WR 1339 considerably decreases the equilibrium density of structures bearing invertase. Nevertheless invertase distribution is quite distinct from that of the bulk of lysosomal enzymes that are recovered in lower density zones of the gradient; on the other hand the invertase injection to rats treated with Triton WR 1339 causes a spreading of the acid hydrolase distribution towards higher density zones. The distribution of acid hydrolases and invertase in a Percoll gradient depends on the sucrose concentration of the solvent. It is shifted towards higher densities when the sucrose concentration increases. The phenomenon is more important for invertase. These results are best explained by supposing that invertase accumulates in a distinct population of lysosomes that can be individualized as a result of the density increase they are subjected to by the invertase they accumulate. It is proposed that these lysosomes mainly originate from non-parenchymal cells of the liver.
通过对注射后15小时处死的大鼠线粒体组分在蔗糖和Percoll梯度中进行分析离心，研究了大鼠肝脏内吞的转化酶的细胞内定位。在蔗糖梯度中进行等密度离心后，转化酶位于比酸性水解酶更高密度的区域。转化酶和酸性水解酶分布的差异随着注射的转化酶量增加而增大。当转化酶剂量足够高时，溶酶体酶分布的变化清晰可见。这表现为一部分这些酶向转化酶所在的更高密度区域转移。对于所测量的每种酶，受转化酶影响的水解酶活性比例不同；酸性磷酸酶受影响最小，酸性脱氧核糖核酸酶和芳基硫酸酯酶受影响最大。用曲拉通WR 1339预处理大鼠会显著降低承载转化酶的结构的平衡密度。然而，转化酶的分布与在梯度较低密度区域回收的大部分溶酶体酶的分布明显不同；另一方面，向用曲拉通WR 1339处理的大鼠注射转化酶会导致酸性水解酶分布向更高密度区域扩展。酸性水解酶和转化酶在Percoll梯度中的分布取决于溶剂的蔗糖浓度。当蔗糖浓度增加时，其向更高密度转移。这种现象对转化酶更为重要。这些结果最好通过假设转化酶积聚在一个独特的溶酶体群体中来解释，由于它们积聚的转化酶使其密度增加，这些溶酶体可以被区分出来。有人提出这些溶酶体主要起源于肝脏的非实质细胞。
