ABSTRACT
Objective:To investigate the m echanism of D- amino acid oxidase/D- Alanine system in killing K5 6 2 e cells in vitro.Methods:The killing effects of D- Ala on K5 6 2 e cells stably expressing DAAO and GFP were observed.H2 O2 production by DAAO+ cells were m easured by the phenol red oxidation assay.L owry method was used to determ ine the protein quantities of cells and fluorescent intensities of GFP+ cells were assayed by flow cytom eter.Results:KDf Gd cells were killed completely after treated with 2 5 mm ol/L D- Ala for 2 4 h.The effect of D - Ala at 2 0 m mol/L on KDf Gd cells increased apparently within 4 8h,but the same effect was not observed if D - Ala was below 15 m mol/L .The cytotoxicity of D- Ala in KDf Gd cells was more sensitive than in parental K 5 6 2 e cells.The H2 O2 levels in the medium were consistent with the killing effects of D- Ala.Conclusion:The killing effects of DAAO/D- Ala system is m ediated by H2 O2 . [