Enzyme-to-enzyme channelling in the early steps of glycolysis in rat pancreatic islets.
Int J Biochem Cell Biol
; 36(8): 1510-20, 2004 Aug.
Article
en En
| MEDLINE
| ID: mdl-15147730
ABSTRACT
The metabolism of D-glucose displays anomeric specificity in rat pancreatic islets. The aim of the present report is to investigate whether such a situation implies enzyme-to-enzyme tunnelling of metabolites in the early steps of glycolysis. For such a purpose, the modelling of alpha- and beta-D-glucose catabolism, itself based on available information concerning both the utilisation of these two anomers and the intrinsic properties of phosphoglucoisomerase, was first examined. According to a theoretical model with enzyme-to-enzyme channelling, the generation of 3HOH from D-[2-3H]glucose should be higher in islets exposed to beta-D-glucose rather than alpha-D-glucose, whilst the opposite situation should prevail in the case of D-[5-3H]glucose conversion to 3HOH. Experimental data collected in rat islets incubated for 60 min at 4 degrees C in the presence of either alpha- or beta-D-glucose mixed with tracer amounts of either alpha- or beta-D-[2- 3H]glucose and alpha- or beta-D-[5-3H]glucose indicate that the beta/alpha ratio for D-[2-3H]glucose conversion to 3HOH is indeed higher than the beta/alpha ratio for D-[5-3H]glucose conversion to 3HOH. These findings are consistent with the postulated enzyme-to-enzyme tunnelling of glycolytic intermediates between hexokinase isoenzyme(s), phosphoglucoisomerase and, possibly, phosphofructokinase.
Buscar en Google
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Islotes Pancreáticos
/
Enzimas
/
Glucólisis
Tipo de estudio:
Prognostic_studies
Límite:
Animals
Idioma:
En
Revista:
Int J Biochem Cell Biol
Asunto de la revista:
BIOQUIMICA
Año:
2004
Tipo del documento:
Article
País de afiliación:
Bélgica