Cytochrome P450 Monooxygenases Catalyse Steroid Nucleus Hydroxylation with Regio‐ and Stereo‐Selectivity.

Steroids are the second largest class of drugs with a wide range of pharmacological properties. Hydroxylation of steroids seriously affects their biological activities and other properties. However, steroids are mostly sp3 hybridized carbons with numerous C−H bonds far from the functional group that can activate them, and achieving regio‐ and stereo‐selective hydroxylation on steroids is a highly challenging task that is almost impossible to achieve using modern organic synthesis techniques. Interestingly, cytochrome P450 monooxygenases possess the ability to catalyse regio‐ and stereo‐selective oxidations of nonactivated C−H bonds in complex organic molecules under mild conditions. This review summarizes the P450s identified and engineered in recent years that can catalyse steroid nucleus hydroxylation stereo‐ and regio‐selectively. [ABSTRACT FROM AUTHOR]