Kinetics studies on thermal isomerization of β-N-oxalyl-L-α,β-diaminopropionic acid by capillary zone electrophoresis

Abstract

The reciprocal thermal isomerization in aqueous solution between neurotoxic nonprotein amino acid β-N-oxalyl-L-α,β-diaminopropionic acid (β-ODAP) in seeds of Lathyrussativus (LS; grass pea) and its nontoxic isomer α-N-oxalyl-L-α,β-diaminopropionic acid (α-ODAP) was studied using capillary zone electrophoresis (CZE) in the range from pH=2.5 to pH=13 at T=75°C, and a decrease of the equilibrium concentration ratio of α-ODAP with the increase of pH of the solution was found. In the range of temperatures 55–95°C, The rate constants have been measured and thermodynamic parameters such as activation energy (E_a) and the pre-exponential factor (A) have been calculated.