Carboxylation mechanism and stereochemistry of crotonyl-CoA carboxylase/reductase, a carboxylating enoyl-thioester reductase.

ABSTRACT: Chemo- and stereoselective reductions are important reactions in chemistry and biology, and reductases from biological sources are increasingly applied in organic synthesis. In contrast, carboxylases are used only sporadically. We recently described crotonyl-CoA carboxylase/reductase, which catalyzes the reduction of (E)-crotonyl-CoA to butyryl-CoA but also the reductive carboxylation of (E)-crotonyl-CoA to ethylmalonyl-CoA. In this study, the complete stereochemical course of both reactions was investigated in detail. The pro-(4R) hydrogen of NADPH is transferred in both reactions to the re face of the C3 position of crotonyl-CoA. In the course of the carboxylation reaction, carbon dioxide is incorporated in anti fashion at the C2 atom of crotonyl-CoA. For the reduction reaction that yiel

SUBMITTER: Erb TJ 

PROVIDER: S-EPMC2689996 | biostudies-literature | 2009 Jun

REPOSITORIES: biostudies-literature