Structures, Functions and Medical Meaning of Lysosomal Cysteine Protease Inhibitors

我们纯化了溶酶体半胱氨酸蛋白酶、组织蛋白酶B、H和L，并确定了组织蛋白酶B和H的氨基酸序列和碳水化合物结构。观察了三种导管在不同器官和外周血细胞中的分布和定位。组织蛋白酶B的含量在吞噬细胞如巨噬细胞和枯否细胞中极高，并且在炎性巨噬细胞中被诱导数倍。三种组织蛋白酶在肝细胞、胰岛细胞和脑中的定位不同。半<alpha>胱氨酸蛋白酶<beta>抑制剂和内源性半胱氨酸蛋白酶抑制剂进行测序，并证明其不同的组织分布。胱抑素的半胱氨酰残基（cys-3）<beta>通过与谷胱甘肽形成混合二硫化物参与抑制活性的调节：游离形式具有活性，谷胱甘肽化形式无活性。抑制剂的混合二硫化物的形成显示在培养的细胞中发生，推测是通过酶促反应。本文研究了不同营养和激素条件下肝细胞自噬和异噬的不同调节与三种组织蛋白酶在肝细胞中不同定位的关系。自噬和组织蛋白酶的升高在肌肉消耗性疾病的肌纤维中显示出显著的加速关系，例如具有镶边空泡的远端肌病和Duchnne型肌肉营养不良，这表明在这些疾病中抑制半胱氨酸组织蛋白酶有望抑制肌肉萎缩的进展。

We purified lysosomal cysteine proteinases, cathepsins B, H and L and determined the amino acid sequences and carbohydrate structures of cathepsin B and H. Distributions and localizations of three cathepsis in various organs and peripheral blood cells were examined. The content of cathepsin B is extremely high in phagocytes such as macrophages and Kupffer cells and it is induced several fold in inflammatory macrophages. Different localizations of three cathepsins were shown in hepatocytes, pancreatic islet cells and brain. Cystatin <alpha> and <beta> , endogenous cysteine proteinase inhibitors were sequenced and their different tissue distributions were demonstrated. A cysteinyl residue (cys-3) of cystatin- <beta> is involved in regulation of the inhibitory activity by formation of mixed disulfide with glutathione: free form is active and the glutathionated form is inactive. The formation of mixed disulfide of the inhibitor was shown to occur in cultured cells, presumably by the enzymatic reaction. Different regulation of autophagy and heterophagy in liver under various nutritional and hormonal conditions was studied in relating with different localizations of three cathepsins in hepatocytes. Marked accerelation of autophagy and elevation of cathepsins were shown in myofibers of muscle wasting diseases such as distal myopathy with rimmed vacuole and Duchnne type muscle dystrophy, suggesting that the inhibition of cysteine cathepsins in these diseases is expected to supress the progression of muscle atrophy.