Banno Y, Sasaki N, Nozawa Y
Exp Cell Res. 1987 Jun;170(2):259-68. doi: 10.1016/0014-4827(87)90304-1.
A number of lysosomal enzymes are secreted from Tetrahymena pyriformis during growth and during starvation. The secretion is energy-dependent and kinetically different among hydrolases. On the basis of the secretion kinetics under starvation conditions, Tetrahymena hydrolases can be separated into three classes. The first group containing acid phosphatase, beta-glucosidase and alpha-galactosidase, are secreted slowly. Within this group about 4% of the initial cellular activity is released per hour. The second group of enzymes, including alpha-glucosidase, alpha-mannosidase and beta-galactosidase, exhibit moderate secretion (11-15% of the initial cellular activity per hour). The third group, N-acetyl-beta-hexosaminidase, has the highest rate of secretion (22% of the initial cellular activity per hour). N-Acetyl-beta-hexosaminidase shows a continuous increase in overall activity during starvation, which is completely blocked by adding cycloheximide; its secretion is also suppressed. Such involvement of enzyme biosynthesis was not seen in the first and second groups. Furthermore, treatment with weak bases caused inhibited secretion of differing degree among acid phosphatase (group I), alpha-glucosidase (group II) and N-acetyl-beta-hexosaminidase (group III).
在生长和饥饿期间，梨形四膜虫会分泌多种溶酶体酶。这种分泌是能量依赖型的，并且在不同水解酶之间存在动力学差异。根据饥饿条件下的分泌动力学，梨形四膜虫的水解酶可分为三类。第一组包括酸性磷酸酶、β-葡萄糖苷酶和α-半乳糖苷酶，分泌缓慢。在这一组中，每小时约有4%的初始细胞活性被释放。第二组酶，包括α-葡萄糖苷酶、α-甘露糖苷酶和β-半乳糖苷酶，表现出中等程度的分泌（每小时初始细胞活性的11 - 15%）。第三组，N-乙酰-β-己糖胺酶，具有最高的分泌速率（每小时初始细胞活性的22%）。N-乙酰-β-己糖胺酶在饥饿期间总体活性持续增加，添加环己酰亚胺可完全阻断这种增加；其分泌也受到抑制。在第一组和第二组中未观察到这种酶生物合成的参与。此外，用弱碱处理会导致酸性磷酸酶（第一组）、α-葡萄糖苷酶（第二组）和N-乙酰-β-己糖胺酶（第三组）的分泌受到不同程度的抑制。
