Threonine aldolases (TAs) are pyridoxal-5-phosphate (PLP)-dependent enzymes that catalyze the reversible aldol condensation between aldehydes and glycine, enabling the asymmetric synthesis of chiral β-hydroxy-α-amino acids. The discovery of new TAs has greatly enriched the enzyme family and spurred investigations into noncanonical reactions beyond conventional aldol condensation, establishing access to structurally diverse amino compounds. Protein engineering has significantly improved the catalytic performance of this enzyme class, particularly addressing the inherent limitation of low Cβ-stereoselectivity. Furthermore, the integration of TAs into multi-enzyme cascade systems has broadened their synthetic applicability. This review systematically presents recent progress in biocatalysis with TAs, including the various reaction types, the engineering of LTAs for improved catalytic performance, the application of the enzyme in cascade reactions, and future opportunities to broaden the utility of the enzyme class in amino compound synthesis.
Li et al. (Mon,) studied this question.