Pote M S, Altekar W
Biochim Biophys Acta. 1981 Oct 13;661(2):303-14. doi: 10.1016/0005-2744(81)90019-x.
Stress dependent variations in th properties of the rat muscle aldolase (D-fructose-1,6-bisphosphate D-glyceraldehyde-3-phosphate-lyase, EC 4.1.2.13) have been linked to the corresponding changes in the levels of proteolytic activities in rat muscle. Whole-body X-irradiation of rat was shown to result in loss of muscle aldolase activity towards fructose 1,6-bisphosphate by 50% while fructose 1-phosphate activity remained unchanged (Pote, M.S. and Altekar, W. (1980) Ind. J. Biochem, Biophys. 17, 255-262). Incubation of muscle extract of irradiated rat with that from control rat or rabbit muscle aldolase caused similar changes in aldolase activity. The changes are attributed to the action of catheptic enzymes possessing latency characteristics and capable of using aldolase as a substrate; the time course of their increase after irradiation corresponds to that of loss in muscle aldolase activities. Exposure of rats to stress resulted in an increase in the 'free' proteolytic activity, and the concomitant loss of 'bound' activity in muscle lysosomes indicates labilization of lysosomal membrane. The observed degradation of aldolase in vivo by muscle lysosomes is shown to be due to the action of cathepsin B (EC 3.4.22.1) present in the proteolytic enzymes released into cytosol under stress. Inactivation of rabbit muscle aldolase and rat muscle aldolase by rat muscle cathepsin B inhibited by leupeptin, antipain an iodoacetamide, but not be pepstatin. Inactivation is shown to be due to the release of C-terminal tyrosine if aldolase, required for its catalytic activity. Cathepsin B who acts as a rate-limiting enzyme in the degradation of aldolase. Such a proteolytic modification of aldolase in vivo could be relevant not only to the regulation of aldolase activity of glycolysis in muscle but also to the degradation of aldolase during stress conditions related to tissue damage and the maintenance of normal aldolase levels in the blood.
大鼠肌肉醛缩酶（D-果糖-1,6-二磷酸 D-甘油醛-3-磷酸裂解酶，EC 4.1.2.13）的应激依赖性变化与大鼠肌肉中蛋白水解活性水平的相应变化有关。对大鼠进行全身 X 射线照射后，肌肉醛缩酶对果糖 1,6-二磷酸的活性丧失了 50%，而对果糖 1-磷酸的活性保持不变（波特，M.S. 和阿尔特卡尔，W.（1980 年）《印度生物化学与生物物理学杂志》17 卷，255 - 262 页）。将受照射大鼠的肌肉提取物与对照大鼠或兔肌肉醛缩酶一起孵育，会导致醛缩酶活性发生类似变化。这些变化归因于具有潜伏特性且能够将醛缩酶作为底物的组织蛋白酶的作用；照射后它们活性增加的时间进程与肌肉醛缩酶活性丧失的时间进程一致。使大鼠暴露于应激状态会导致“游离”蛋白水解活性增加，而肌肉溶酶体中“结合”活性的相应丧失表明溶酶体膜不稳定。观察到的肌肉溶酶体在体内对醛缩酶的降解是由于应激状态下释放到细胞质中的蛋白水解酶中存在的组织蛋白酶 B（EC 3.4.22.1）的作用。大鼠肌肉组织蛋白酶 B 使兔肌肉醛缩酶和大鼠肌肉醛缩酶失活，这种失活可被亮抑酶肽、抗蛋白酶和碘乙酰胺抑制，但不能被胃蛋白酶抑制剂抑制。已表明失活是由于醛缩酶催化活性所需的 C 末端酪氨酸的释放。组织蛋白酶 B 在醛缩酶降解过程中起限速酶的作用。醛缩酶在体内的这种蛋白水解修饰不仅可能与肌肉中糖酵解的醛缩酶活性调节有关，还可能与组织损伤相关应激条件下醛缩酶的降解以及血液中醛缩酶正常水平的维持有关。
