Mechanism and substrate stereochemistry of 2-amino-3-oxobutyrate CoA ligase: implications for 5-aminolevulinate synthase and related enzymes.

The condensation process catalysed by 2-amino-3-oxobutyrate CoA ligase (KBL; also known as 2-amino-3-ketobutyrate ligase) involves the loss of the pro-R hydrogen atom of glycine and occurs with the inversion of stereochemistry; a similar scenario is envisaged for the condensation step of other alpha-oxoamine synthases.