Ectoenzymes of the kidney microvillar membrane. Affinity purification, characterization and localization of the phospholipase C-solubilized form of renal dipeptidase.
Renal dipeptidase (EC 3.4.13.11) 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 3.4.24.11). 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.
Littlewood
G M
GM
Department of Biochemistry, University of Leeds, U.K.
Hooper
N M
NM
Turner
A J
AJ
D000818:Animals; D003429:Cross Reactions; D004150:Dipeptidases / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism*; D004791:Enzyme Inhibitors; D007668:Kidney / Q000201:enzymology* / Q000648:ultrastructure; D008871:Microvilli / Q000201:enzymology*; D012995:Solubility; D013552:Swine
D004791:Enzyme Inhibitors; D004150:Dipeptidases; C038937:dipeptidase