Nishi N, Kagawa Y, Miyanaka H, Oya H, Wada F
Department of Endocrinology, Kagawa Medical School, Japan.
Biochim Biophys Acta. 1992 Jul 21;1117(1):47-54. doi: 10.1016/0304-4165(92)90161-m.
Immunoblotting with a monoclonal antibody against probasin (rat prostatic secretory protein) showed that a 40-kDa protein antigenically related to probasin was localized in rat liver and kidney. The contents of probasin in these organs were negligible. Immunostaining revealed that the 40-kDa protein (probasin-related antigen: PRB-RA) was expressed in the liver parenchymal cells and the kidney urinary tubular epithelial cells in outer stripe. The content of PRB-RA in the kidney was low during 0 to 2 weeks of age, then rapidly increased about 10-fold from 2 to 8 weeks of age. The content in the liver increased about 2-fold during the period, reaching a value of 10-12 ng/micrograms protein, which was ten times higher than that in the kidney. PRB-RA was purified from rat liver by ion-exchange chromatography, gel filtration and fast protein liquid chromatography on a hydroxyapatite column. The purified protein formed insoluble aggregates in the absence of a detergent, and it had a blocked amino terminal. The amino acid sequence of a peptide generated by tryptic digestion of alkylated PRB-RA was determined. Computer analysis showed that there was no protein having a significant homology with the peptide. These results indicate that a novel 40-kDa protein with a structural similarity to probasin is localized in rat liver and kidney, and might bear a function specific to these organs.
用抗前列腺素（大鼠前列腺分泌蛋白）的单克隆抗体进行免疫印迹分析表明，一种与前列腺素抗原相关的40 kDa蛋白定位于大鼠肝脏和肾脏。这些器官中前列腺素的含量可忽略不计。免疫染色显示，40 kDa蛋白（前列腺素相关抗原：PRB - RA）在外带的肝实质细胞和肾肾小管上皮细胞中表达。在0至2周龄时，肾脏中PRB - RA的含量较低，然后在2至8周龄时迅速增加约10倍。在此期间，肝脏中的含量增加约2倍，达到10 - 12 ng/μg蛋白质的值，这比肾脏中的含量高10倍。通过离子交换色谱、凝胶过滤和羟基磷灰石柱快速蛋白质液相色谱从大鼠肝脏中纯化PRB - RA。纯化后的蛋白质在没有去污剂的情况下形成不溶性聚集体，并且其氨基末端被封闭。测定了烷基化PRB - RA经胰蛋白酶消化产生的肽段的氨基酸序列。计算机分析表明，没有与该肽段具有显著同源性的蛋白质。这些结果表明，一种与前列腺素结构相似的新型40 kDa蛋白定位于大鼠肝脏和肾脏，并且可能具有这些器官特有的功能。
