lysosomal的抑制剂：leupeptin or chloroquine?最近正在反复研究蛋白降解途径的问题，我试着给你提供些信息，希望对你有帮助： 你们讨论的问题中把我想告诉你的东西说到了一些。蛋白降解途径目前讨论得比较多的是三条：溶酶体、钙依赖途径和泛素－蛋白酶体系统。lysosomes-These organelles contain several acid-optimal proteases, including cathepsins B, H, and D, and many other acid hydrolases...It is possible to quantitate the contribution of the lysosomes to a proteolytic process by using agents that block lysosomal acidification (e.g., chloroquine and methylamine) or by using inhibitors of the lysosomal cysteine proteases, cathepsins B, H, and L (e.g., leupeptin or E64) (Furuno and Goldberg 1986). Use of these inhibitors has demonstrated that the lysosomal pathway is mainly involved in degrading surface membrane proteins and endocytosed, extracellular proteins, rather than having a major role in the normal turnover of cytosolic proteins under normal conditions (Furuno and Goldberg 1986, Lowell et al. 1986). One Ca21-activated (ATP-independent) proteolytic process involves the cysteine proteases termed calpains (Mellgren 1987, Murachi et al. 1980, Waxman 1981). Like many lysosomal proteases, these enzymes are inhibitable by E64 and leupeptin. Two forms of calpains have been described which differ in their affinity for Ca21. A specific protein inhibitor of the calpains, calpistatin, is also present in mammalian cytosol and is able to bind and inactivate four calpain molecules (Murachi et al. 1980). These proteases appear to be activated when cells are injured and cytosolic Ca21 rises, and so they may play an important role in tissue injury, necrosis and autolysis (Goll et al. 1992). However, it is still unclear whether they function in the normal turnover of any cell proteins (Furuno and Goldberg 1986). 第三条就是2004年得了若贝尔奖的泛素－蛋白酶体系统，资料多的是，我就不多说了。正如你们俩讨论到的，leupeptin不但能抑制蛋白降解途径一，根据我的引述，还能抑制途径二，还能抑制途径三。试想，这种抑制剂既然能同时抑制以上三种途径，你的结果显然不够让人信服，我觉得应该补充calpain抑制剂和泛素－蛋白酶体系统抑制剂的试验。同时，根据文献，蛋白降解途径一和二都主要在细胞的非常态情况下发挥作用，而第三途径既能在常态也能在应激情况下发挥主导作用。由于不知道您研究的蛋白质究竟是什么，所以不好推论什么，根据上面的信息您应该自己能推论出来。我个人认为，一般情况下，这种蛋白质越重要，它受到上述三条途径的降解可能性越大，而不是仅仅收到其一之调控！ 查看更多
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