Characterization of ATP-dependent monoglucuronosyl bilirubin transport across rat canalicular membrane vesicles.
Hepatol Res
; 19(2): 103-107, 2001 Feb.
Article
em En
| MEDLINE
| ID: mdl-11164735
ABSTRACT
Bilirubin conjugates are secreted from hepatocytes into bile. Monoglucuronosyl bilirubin is an endogenous substrate for the multidrug resistance protein 2, which is located in rat hepatocyte canalicular membrane. We have characterized this ATP-dependent transport using rat canalicular membrane vesicles. Monoglucuronosyl bilirubin, 3H-labeled in the glucuronosyl moiety, was synthesized enzymatically using recombinant UDP-glycosyltransferase 1A1, and was stabilized with ascorbate. The rate for ATP-dependent transport of monoglucuronosyl bilirubin (at 0.5 µM) was 7.3+/-1.1 pmol mg protein(-1) min(-1) and the K(m) value was 1.3+/-0.4 µM. This is the first time to demonstrate this kinetic constant of monoglucuronosyl bilirubin for the rat hepatocyte canalicular membrane. The K(m) value is similar to one for recombinant rat multidrug resistance protein 2.
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Base de dados:
MEDLINE
Idioma:
En
Revista:
Hepatol Res
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Alemanha