A chiral ligand exchange CE essay with zinc(II)–l-valine complex for determining enzyme kinetic constant ofl-amino acid oxidase

Li Qi, Gengliang Yang, Haizhi Zhang, Juan Qiao, Li Qi, Gengliang Yang, Haizhi Zhang, Juan Qiao, Li Qi, Gengliang Yang, Haizhi Zhang, Juan Qiao

Index: Talanta 81(4-5) , 1554-9, (2010)

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Abstract

A new strategy for the enantioseparation of d, l-amino acids employing the principle of ligand exchange capillary electrophoresis with Zn(II)– l-valine complex as a chiral selecting system in the presence of β-cyclodextrin has been designed. Successful enantioseparation of label free and labeled amino acids have been achieved with a buffer of 100.0 mM boric acid, 5.0 mM ammonium acetate, 4.0 mM β-cyclodextrin, 4.0 mM ZnSO 4 and 8.0 mM l-valine at pH 8.1. This new method was shown to be applicable to the quantitative analysis of label free d- and l-aromatic amino acids. Furthermore, the expanding enzymatic use of l-amino acid oxidase to incubate with different l-amino acids has allowed understanding of the substrate's specificity. An on-column incubation assay has been developed to study the l-amino acid oxidase's catalytic efficiency. It was demonstrated that the enzyme kinetic constant could be determined by using this new method.