Epimerase activity of the human 11β-hydroxysteroid dehydrogenase type 1 on 7-hydroxylated C19-steroids

Cytochrome P4507B1 7α-hydroxylates dehydroepiandrosterone (DHEA), epiandrosterone (EpiA) and 5α-androstane-3β,17β-diol (Adiol). 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) interconverts 7α- and 7β-forms. Whether the interconversion proceeds through oxido-reductive steps or epimerase activity was investigated. Experiments using [(3)H]-labelled 7β-hydroxy-DHEA, 7β-hydroxy-EpiA and 7β-hydroxy-Adiol showed the (3)H-label to accumulate in the 7-oxo-DHEA trap but not in 7-oxo-EpiA or 7-oxo-Adiol traps. Computed […]

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