Enantioselective High‐Throughput Assay Showcased for the Identification of (R)‐ as well as (S)‐Selective Unspecific Peroxygenases for C−H Oxidation

Abstract

AbstractIdentifying (bio)catalysts displaying high enantio‐/stereoselectivity is a fundamental prerequisite for the advancement of asymmetric catalysis. Herein, a high‐throughput, stereoselective screening assay is reported that gives information on enantioselectivity, stereopreference and activity as showcased for peroxygenase‐catalyzed hydroxylation. The assay is based on spectrophotometric analysis of the simultaneous formation of NAD(P)H from the alcohol dehydrogenase catalyzed enantioselective oxidation of the sec‐alcohol product formed in the peroxygenase reaction. The assay was applied to investigate a library comprising 44 unspecific peroxygenases (UPOs) containing 25 UPOs not reported yet. Thereby, previously non‐described wild‐type UPOs displaying (S)‐ as well as (R)‐stereoselectivity for the hydroxylation of representative model substrates were identified, reaching up to 98 % ee for the (R)‐ and 94 % ee for the (S)‐enantiomer. Homology models with concomitant docking studies indicated the structural reason for the observed complementary stereopreference.