Renal dipeptidase (EC 18.104.22.168) was solubilized from pig kidney microvillar membranes with bacterial phosphatidylinositol-specific phospholipase C and then purified by affinity chromatography on cilastatin-Sepharose. The enzyme was apparently homogeneous on SDS/polyacrylamide-gel electrophoresis with an Mr of 47,000. Immunohistochemical analysis of the distribution of the dipeptidase showed it to be concentrated in the brush-border region of the proximal tubules in close association with endopeptidase-24.11) (EC 22.214.171.124). The purified dipeptidase was shown to contain 1 mol of inositol/mol and to possess the cross-reacting determinant characteristic of the glycosyl-phosphatidylinositol membrane-anchoring domain. The glycoprotein nature of renal dipeptidase was confirmed by chemical and enzymic deglycosylation. These results establish renal dipeptidase as a glycosyl-phosphatidylinositol-anchored ectoenzyme of the microvillar membrane.
Ectoenzymes of the kidney microvillar membrane. Affinity purification, characterization and localization of the phospholipase C-solubilized form of renal dipeptidase
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G M Littlewood, N M Hooper, A J Turner; Ectoenzymes of the kidney microvillar membrane. Affinity purification, characterization and localization of the phospholipase C-solubilized form of renal dipeptidase. Biochem J 15 January 1989; 257 (2): 361–367. doi: https://doi.org/10.1042/bj2570361
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