Acid phosphatase activity in the mammalian nephron.
Acid phosphatase activity in the mammalian nephron.
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哺乳动物肾单位中的酸性磷酸酶活性。
DOI：
10.1152/ajprenal.1984.247.2.f252
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发表时间：
1984
期刊：
影响因子：
--
通讯作者：
Tisher,CC
中科院分区：
文献类型：
--
作者：
Olbricht,CJ;Garg,LC;Cannon,JK;Tisher,CC
采用4-甲基伞形酮磷酸盐作为底物，在大鼠和兔肾单位的单个节段中测定溶酶体酸性磷酸酶（Acetylase）活性。反应产物的生成与孵育时间呈线性关系，最长可达127 min，与小管长度呈线性关系。大鼠肾小球和近曲小管的活性明显高于兔肾。在大鼠和家兔中，髓质的活性均高于浅表肾小球。在大鼠中，从S1到S3节段，Acceptor活性降低，这与已知的溶酶体数量减少平行。令人惊讶的是，在两种性别的家兔中，皮质集合管（CCD）中的Acceptor活性（包含有限数量的溶酶体）与近端小管S1和S2段中测得的水平相当。同样，在雄性大鼠中，皮质厚升支、远曲小管、CCD和髓集合管中的Acceptor活性值与S3段中的值相同。这些结果表明，在远端肾单位中有相当数量的Acrylate是溶酶体外的，或者与近端小管相比，远端肾单位节段中每单位体积的溶酶体Acrylate活性量更大。在家兔中发现S_1段和CCD中的腺苷酸的Km值不同，表明存在不同的同工酶。
Lysosomal acid phosphatase (AcPase) activity was measured in individual segments of rat and rabbit nephrons employing 4-methylumbelliferyl phosphate as the substrate. Generation of reaction product was linear with incubation time up to 127 min and with tubule length. Activity was much higher in glomeruli and proximal tubules of rat than rabbit kidney. In both rat and rabbit there were higher activities in juxtamedullary than in superficial glomeruli. In rats, AcPase activity decreased from S1 to S3 segments, which parallels the known decrease in the number of lysosomes. Surprisingly, in rabbits of both sexes AcPase activity in the cortical collecting duct (CCD), which contains a limited number of lysosomes, was comparable to levels measured in the S1 and S2 segments of the proximal tubule. Similarly, in the male rat values for AcPase activity in the cortical thick ascending limb, distal convoluted tubule, CCD, and medullary collecting duct paralleled those in the S3 segment. These findings suggest that a considerable amount of AcPase in the distal nephron is either extralysosomal or that the amount of lysosomal AcPase activity per unit volume is greater in distal nephron segments compared with the proximal tubule. Different K'm values for AcPase in S1 segments and CCD were found in the rabbit, suggesting the presence of different isoenzymes.