Effect of low molecular weight proteins and dextran on renal cathepsin B and L activity.
Effect of low molecular weight proteins and dextran on renal cathepsin B and L activity.
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低分子量蛋白和右旋糖酐对肾组织蛋白酶 B 和 L 活性的影响。
DOI：
10.1038/ki.1990.66
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发表时间：
1990
影响因子：
19.6
通讯作者：
Tisher,CC
中科院分区：
文献类型：
--
作者：
Olbricht,CJ;Gutjahr,E;Cannon,JK;Irmler,H;Tisher,CC
低分子蛋白质和右旋糖苷对肾组织蛋白酶B和L活性的影响肾提取的低分子蛋白质(LMWP)占其总代谢清除量的30%~80%。提取包括肾小球滤过、近端小管摄取和溶酶体内蛋白分解。为探讨重吸收低分子量多糖消化的解剖部位和所涉及的酶，用超微量分析方法测定了蛋白尿大鼠近曲小管S1、S2和S3段溶酶体蛋白水解酶组织蛋白酶B和L的含量。静脉注射可增加肾小球滤过率和肾小管摄取LMWP。和IP。肌红蛋白、阳离子和阴离子溶菌酶的注射。阳离子溶菌酶和肌红蛋白均能增加近曲小管组织蛋白酶B和L的活性，而阴离子溶菌酶则无此作用。肾组织的形态检查表明，与阳离子形式相比，近端肾小管对阴离子溶菌酶的摄取可以忽略不计。因此，只有近端小管细胞吸收的LMWP才能刺激组织蛋白酶B和L的活性。通过测量S1、S2和S3中的溶菌酶活性来确定近端肾小管对阳离子溶菌酶的摄取。S1段的溶菌酶活性最高，S2和S3的活性较低，注射阳离子溶菌酶后，组织蛋白酶B和L的活性仅在S1段被激活。这些结果表明，组织蛋白酶B和L参与了某些LMWP的溶酶体消化。组织蛋白酶B和L的活性与LMWP摄取的增加相适应。为了进一步了解组织蛋白酶适应的机制，我们测定了注射类似低分子右旋糖苷后组织蛋白酶B和L的活性。肾组织的形态检查证实近端小管摄取了右旋糖苷。右旋糖苷增加近曲小管组织蛋白酶B和L的活性。因此，近端小管细胞内吞活性的增加或大分子溶酶体负荷的增加，而不是直接的蛋白质-酶相互作用，似乎参与了组织蛋白酶的刺激。
Effect of low molecular weight proteins and dextran on renal cathepsin B and L activity. Renal extraction of low molecular weight proteins (LMWP) accounts for 30% to 80% of their total metabolic clearance. Extraction includes glomerular filtration, proximal tubular uptake, and intralysosomal proteolysis. To characterize the anatomic sites and enzymes involved in digestion of reabsorbed LMWP, the lysosomal proteases, cathepsin B and L, were measured by ultramicroassay in isolated S1, S2 and S3 segments of the proximal tubule of proteinuric rats. Increased glomerular filtration and tubular uptake of LMWP were induced by i.v. and i.p. injections of myoglobin and cationic and anionic lysozyme. Both cationic lysozyme and myoglobin increased cathepsin B and L activities in the proximal tubule, while anionic lysozyme had no effect. Morphologic examination of kidney tissue suggested that proximal tubular uptake of anionic lysozyme was negligible in comparison with the cationic form. Hence, only LMWP absorbed by the proximal tubule cells stimulated cathepsin B and L activities. Proximal tubular uptake of cationic lysozyme was determined by measurement of lysozyme activities in S1, S2, and S3. S1 segments contained the highest lysozyme activity, while S2 and S3 had much lower activities, and cathepsin B and L activity following cationic lysozyme injection was stimulated only in S1 segments. These results suggest that cathepsin B and L participate in lysosomal digestion of certain LMWP. Furthermore, the activities of cathepsin B and L adapt to increased uptake of LMWP. To gain additional insight into the mechanism of cathepsin adaptation, the cathepsin B and L activities were measured following injection of dextran with a similar low molecular weight. Dextran uptake in proximal tubules was confirmed by morphologic examination of kidney tissue. Dextran increased cathepsin B and L activities in the proximal tubule. Hence, increased endocytic activity of proximal tubule cells or increased lysosomal load of macromolecules or both rather than direct protein-enzyme interaction seem to be involved in cathepsin stimulation.
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影响因子：
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作者：
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通讯作者：
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DOI：
10.1042/bj1740655
发表时间：
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期刊：
The Biochemical journal
影响因子：
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作者：
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DOI：
10.1073/pnas.81.4.1253
发表时间：
1984
影响因子：
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作者：
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通讯作者：
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影响因子：
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作者：
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