Steroids regulate many physiological processes. Hydroxysteroid dehydrogenases (HSDs) modulate the levels of steroids in pre- and post-receptor metabolism. The subfamily of 20β-HSD type 2 currently comprises six members from six different species. The zebrafish ortholog converts cortisone to 20β-dihydrocortisone and is involved in the catabolism of the stress hormone cortisol. Here, we elucidated the substrate preferences of all 20β-HSD type 2 enzymes towards a selected panel of steroids. For quantification of the substrates and their respective 20β-reduced products, we first developed and validated a liquid chromatography-mass spectrometry based method. Applying this method to activity assays with recombinantly expressed enzymes, our findings indicate that the 20β-HSD type 2 enzymes catalyze the 20β-reduction of a plethora of steroids of the glucocorticoid biosynthesis pathway. The observed multispecificity among the homologous 20β-HSD type 2 enzymes implies different physiological roles in different species.

中文翻译：

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20β-羟基类固醇脱氢酶2型成员之间的底物多特异性。

类固醇调节许多生理过程。羟基类固醇脱氢酶（HSD）调节受体前后代谢中类固醇的水平。20β-HSD类型2的亚家族目前包括来自六个不同物种的六个成员。斑马鱼直向同源物将可的松转化为20β-二氢可的松，并参与应激激素皮质醇的分解代谢。在这里，我们阐明了所有20β-HSD2型酶对一组特定类固醇的底物偏好。为了定量分析底物及其各自的20β还原产物，我们首先开发并验证了一种基于液相色谱-质谱的方法。将这种方法应用于重组表达酶的活性测定中，我们的发现表明，20β-HSD2型酶催化糖皮质激素生物合成途径中大量类固醇的20β-还原。在同源20β-HSD2型酶之间观察到的多特异性暗示了在不同物种中的不同生理作用。