Revisit of aminotransferase in the genomic era and its application to biocatalysis

Aminotransferases (ATs) have useful applications in the chemical industry because of their capability of introducing amino group into ketones or keto acids as well as their high enantioselectivity and regioselectivity and broad substrate specificity. Abundant protein sequence databases and new powerful tools such as advanced computational structure modeling, multiple sequence analysis, and in vitro evolution have made it possible to understand the detailed reaction mechanisms of various ATs and to isolate and design novel enzymes for unnatural substrates. This, in turn, suggests that developing new integrated approaches to screen ATs are possible, but at the same time poses formidable technical challenges. Here, this paper reviews the use of family profile analysis to find the correlation between the type of ATs and their substrate specificities, the relation between the 3-D structures of ATs and their substrate specificities, and enzyme engineering for the synthesis of unnatural substrates.