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Detoxification of aldehydes and ketones generally proceeds via reduction to their corresponding alcohols, which are then conjugated and eliminated. We focused our interest on 11β-hydroxysteroid-dehydrogenase type 1 (11β-HSD 1), a pluripotent enzyme which physiologically performs the interconversion of active and inactive glucocorticoid hormones, and which also participates in xenobiotic carbonyl compound detoxification. 11β-HSD 1 belongs to the protein superfamily of the short-chain dehydrogenases/reductases (SDR), and has been structurally and functionally characterized. 11β-HSD 1 is a glycosylated membrane protein which is very difficult to purify in an active state. In addition, expression levels in humans differ in a wide range. In order to facilitate biochemical and molecular studies on the significance of human 11β-HSD 1 in detoxification processes, we have successfully performed the overexpression of recombinant human 11β-HSD 1 in the yeast
Pichia pastoris and in
Escherichia coli. Recombinant 11β-HSD 1 from
E. coli was purified to homogeneity and used to generate a polyclonal antibody. The enzyme had no enzymatic activity, possibly due to the lack of glycosylation and/or incorrect folding in
E. coli. In contrast, 11β-HSD 1 overexpressed in
P. pastoris was enzymatically active towards its physiological glucocorticoid substrates as well as towards xenobiotic carbonyl compounds. In western blot experiments the antibody crossreacted with both recombinant 11β-HSD 1 forms and with the native enzyme from mouse and human liver. In conclusion, recombinant 11β-HSD 1 from
P. pastoris serves as a valuable tool for future studies on carbonyl compound detoxification.