Ectoenzymes of the kidney microvillar membrane
نویسندگان
چکیده
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 cilastatinSepharose. The enzyme was apparently homogeneous on SDS/polyacrylamide-gel electrophoresis with an Mr of 47000. 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 endopeptidase24.11) (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.
منابع مشابه
Ectoenzymes of the kidney microvillar membrane. Differential solubilization by detergents can predict a glycosyl-phosphatidylinositol membrane anchor.
The pattern of solubilization of nine kidney microvillar ectoenzymes by a range of detergents distinguished two classes of membrane proteins: those released from the membrane by bacterial phosphatidylinositol-specific phospholipase C and those not so released. The latter group of transmembrane proteins were solubilized efficiently (greater than 80%) by all the detergents examined. In contrast, ...
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