Characteristics and biotechnology applications of aliphatic amino acid hydroxylases belonging to the Fe(II)/α-ketoglutarate-dependent dioxygenase superfamily

The asymmetric hydroxylation of inactive carbon atoms is still an important reaction in the industrial synthesis of valuable chiral compounds such as pharmaceuticals and fine chemicals. Applications of monooxygenation enzymes, like cytochrome P450 monooxygenases, flavin-containing monooxygenases, and Fe(II)/alpha-ketoglutarate-dependent dioxygenases (Fe/alpha KG-DOs), are strongly desired as hydroxylation biocatalysts because they have great advantages in regio- and stereoselectivity of the reactions. Recently, several novel Fe/alpha KG-DOs have been found to catalyze the asymmetric hydroxylation of aliphatic amino acids. Depending on their amino acid sequences, these Fe/alpha KG-DOs catalyze different types of regioselective hydroxylations, or C3-, C4-, and C5-hydroxylation. Additionally, most also have stereoselective sulfoxidation activities. Here, we have reviewed the characterization and process development of this novel functioning group of Fe/alpha KG-DOs.