KYNURENINASE IN ORGANIC-SYNTHESIS - PREPARATION OF GAMMA-HYDROXY-ALPHA-L-AMINO ACIDS

Kynureninase, which is known to catalyze the transaldol reaction betwe en benzaldehyde and kynurenine, accepted many kinds of other aromatic aldehydes and propargyl aldehydes as the substrates to afford novel ga mma-hydroxy-alpha-L-amino acids. The L-configuration of the alpha-carb ons was confirmed by an enzymatic method using both D- and L-amino aci d oxidases. The stereochemistry of the newly formed chiral center (gam ma-position) in major isomers was determined to be R-configuration by the observed NOEs in the NMR spectroscopy of lactones derived from the gamma-hydroxy-alpha-L-amino acids.