Priming ammonia lyases and aminomutases for industrial and therapeutic applications

► Ammonia lyases and aminomutases are emerging in green synthetic routes to chiral amines. ► An ammonia lyase is being explored as an enzyme therapeutic for treating phenylketonuria and cancer. ► The restricted substrate range of the wild-type enzymes limits their widespread application. ► The non-reliance on external cofactors and direct functionalization of an olefinic bond make ammonia lyases attractive biocatalysts for use in the synthesis of natural and non-natural amino acids. ► The approach of combining structure-guided enzyme engineering with efficient mutant library screening has broadened the synthetic scope of these biocatalysts.