Cloning and characterization of a novel carbonyl reductase for asymmetric reduction of bulky diaryl ketones

Abstract:

Asymmetric reduction of bulky diaryl ketones is still one of the challenging tasks in biocatalysis. By genomic data mining, a putative carbonyl reductase gene pascr was found in Pichia pastoris GS115. pascr was cloned and over-expressed in Escherichia coli Rosseta2 (DE3). The recombinant enzyme was purified to homogeneity by Ni-NTA column and its catalytic properties were studied. PasCR strictly used NADPH as cofactor, gel filtration and SDS-PAGE analysis suggested that the native form of PasCR was a dimmer. PasCR exhibited the highest activity at 35 °C in phosphate buffer at pH 6.5. The enzyme catalyzed the reduction of some bulky diaryl ketones, such as 4-methylbenzophenone, 2-methylbenzophenone and 4-chlorobenzophenone, especially for 4-methylbenzophenone, the product S - alcohol was obtained with 85% ee.