INHIBITIONS OF CATHEPSIN-B AND CATHEPSIN-L BY E-64 INVIVO .2. INCORPORATION OF [H-3]-LABELED E-64 INTO RAT-LIVER LYSOSOMES INVIVO
INHIBITIONS OF CATHEPSIN-B AND CATHEPSIN-L BY E-64 INVIVO .2. INCORPORATION OF [H-3]-LABELED E-64 INTO RAT-LIVER LYSOSOMES INVIVO
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DOI：
10.1093/oxfordjournals.jbchem.a133825
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发表时间：
1982-01-01
影响因子：
2.7
通讯作者：
KATUNUMA, N
中科院分区：
文献类型：
--
作者：
HASHIDA, S;KOMINAMI, E;KATUNUMA, N
E-(N-[N-(L-3-trans-carboxyoxiran-2-carbonyl)-L-leucyl]-agmatine)是一种特异性的硫醇蛋白水解酶抑制剂，在体外抑制溶酶体组织蛋白B和L，体内给药的E-可能是通过渗透而不是内吞进入肝脏的溶酶体。大鼠腹腔注射[~3H]E-后，短时间内血清中放射性较高，随后迅速下降。注射后1h，肝细胞浆[~3H]E-掺入量也开始下降。线粒体溶酶体部分的放射性在6h后达到最大值，然后逐渐下降，直到72h，在所有剂量下，[~3H]E-掺入血清和肝细胞浆均呈剂量依赖关系，但只有当剂量达到0.5 mg/100体重时，[~3H]E-掺入溶酶体部分的量才呈线性增加。E-在血清和肝细胞浆中主要以游离态存在，而在溶酶体组分中主要以蛋白质结合形式存在。E-作用下溶酶体组织蛋白酶B活性的时程和剂量效应与溶酶体蛋白结合部分的放射性密切相关。E-可能在血液中以游离形式转运到肝脏胞浆，并渗透到溶酶体中，在那里它与E-敏感的蛋白水解酶结合并失活。
E-64 (N-[N-(L-3-trans-carboxyoxiran-2-carbonyl)-L-leucyl]-agmatine) is a specific thiol proteinase inhibitor which inhibits lysosomal cathepsins B and L in vitro and in vivo E-64 administered in vivo penetrates into lysosomes of the liver, possibly by permeation rather than by endocytosis. When [3H]E-64 was injected into rats i.p., high radioactivity was observed in the serum after a short time and it decreased rapidly. Incorporation of [3H]E-64 into the cytosol fraction of liver also began to decrease 1 h after the injection. Radioactivity in the mitochondrial-lysosomal fraction increased to a maximum after 6 h and then gradually decreased until 72 h. Dose-dependent incorporation of [3H]E-64 into the serum and liver cytosol was observed at all doses tested, but that into the lysosomal fraction increased linearly with doses of only up to 0.5 mg/100 body weight of E-64. E-64 in the serum and liver cytosol was mostly present in the free form, whereas that in the lysosomal fraction was mostly protein-bound. The time course and dose-response of lysosomal cathepsin B activity to E-64 were closely related to the radioactivity in the protein-bound fraction of the lysosomes. E-64 was probably transported to the liver cytosol in the free form in the blood and permeated into the lysosomes, where it bound to, and inactivated, E-64 sensitive proteinases.