INVESTIGADORES
SANCHEZ POZZI Enrique Juan
artículos
Título:
Analysis of the interaction Uridin 5'-Diphosphoglucuronic acid with intestinal bilirubin UDP-Glucuronyltransferase
Autor/es:
ENRIQUE JUAN SANCHEZ POZZI; RODRÍGUEZ GARAY, EMILIO A; MOTTINO, ALDO D
Revista:
INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND CELLULAR BIOLOGY
Editorial:
PERGAMON-ELSEVIER SCIENCE LTD
Referencias:
Lugar: Amsterdam; Año: 1992 vol. 24 p. 1429 - 1434
ISSN:
1357-2725
Resumen:
1. Bilirubin UDP-glucuronyltransferase Michaelis-Menten kinetic parameters for UDP-glucuronic acid were studied using native and digitonin activated microsomes obtained from rat intestinal mucosa. 2. The intestinal
enzyme showed a lower apparent Vmax compared with the hepatic enzyme in
both native and activated microsomes; digitonin pretreatment enhanced
Vmax 4 times in the former enzyme and 2 times in the latter. 3. The
affinity of UDP-glucuronic acid for the intestinal
enzyme was about 2 times lower than that for the hepatic enzyme and it
was not substantially modified by detergent neither in the intestine nor
in the liver. 4. The lipid analysis of intestinal
and hepatic microsomes showed that the former present a higher content
of cholesterol and a lower phosphatidylcholine/sphingomyelin ratio than
the latter, accordingly the estimation of membrane fluidity using the
fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene indicated that intestinal
microsomes are more "rigid" than the hepatic ones. 5. These
characteristics would provoke a restrictive milieu surrounding the
enzyme that modifies its kinetic properties thus limiting its
participation in the metabolism of bilirubin.