Cooperativity between 11β-hydroxysteroid dehydrogenase type 1 and hexose-6-phosphate dehydrogenase in the lumen of the endoplasmic reticulum

Gábor Bánhegyi, Angelo Benedetti, Rosella Fulceri, Silvia Senesi

Research output: Contribution to journalArticle

142 Citations (Scopus)

Abstract

The functional coupling of 11β-hydroxysteroid dehydrogenase type 1 and hexose-6-phosphate dehydrogenase was investigated in rat liver microsomal vesicles. The activity of both enzymes was latent in intact vesicles, indicating the intraluminal localization of their active sites. Glucose-6-phosphate, a substrate for hexose-6-phosphate dehydrogenase, stimulated the cortisone reductase activity of 11β-hydroxysteroid dehydrogenase type 1. Inhibition of glucose-6-phosphate uptake by S3483, a specific inhibitor of the microsomal glucose-6-phosphate transporter, decreased this effect. Similarly, cortisone increased the intravesicular accumulation of radioactivity upon the addition of radiolabeled glucose-6-phosphate, indicating the stimulation of hexose-6-phosphate dehydrogenase activity. A correlation was shown between glucose-6-phosphate-dependent cortisone reduction and cortisone-dependent glucose-6-phosphate oxidation. The results demonstrate a close cooperation of the enzymes based on co-localization and the mutual generation of cofactors for each other.

Original languageEnglish
Pages (from-to)27017-27021
Number of pages5
JournalJournal of Biological Chemistry
Volume279
Issue number26
DOIs
Publication statusPublished - Jun 25 2004

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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