2,4-二硝基氟苯柱前衍生法测定植物中谷氨酸脱羧酶的活力

A validated, selective, and sensitive chromatographic method for the determination of glutamate decarboxylase (GAD) activity in plant tissues by determining γ-aminobutyric acid (GABA) has been developed using a single (gradient) system. The plant tissues were reacted with substrate L-glutamic acid at 40 ℃ for 2 h before test. Determination was carried out by pre-column reaction of the samples with 2,4-dinitrophenylhydrazine (FDNB) and separating the corresponding derivatives with a reversed phase HPLC on a 5 micro Lichrospher C18 column and UV detection (360 nm). A linear quantitative response curve was generated over a concentration range of 0.2-5 g/L GABA with a correlation coefficient of 0.9954. The precision of this method is high (RSD=0.21%). This method also possesses high recovery rate (＞99%) and good stability. The exprimental results showed that the rice germ and rice bran had relatively high GAD activity, and the GAD activity of brown rice was as good as tea leaves. The method is specific for the determination of GAD activity inplant, and can be adopted in the determination of GABA content in food or bio-systems.