Abstract :
The enantiomeric reaction of glutamate 1-semialdehyde aminotransferase (GSA-AT) with the (R) enantiomer of GSA was investigated. Addition of (R,S)-GSA to the aminotransferase resulted in the transformation of the enzyme into pyridoxal-P or internal aldimine form instead of the original pyridoxamine-P. Treatment with (R,S)-4, 5-diaminovalerate (DAVA) remove this effect on the enzyme by GSA and promotes initial rates of 5-aminolevulinate. The results suggested an anomalous reactivity of (R)-GSA towards GSA-AT and a rate-limiting activity of DAVA for the anomalous enantiomeric reaction.