%A %T Molecular Structure of Two Glutamate Decarboxylases From Mung Bean [Vigna Radiate (L.)] Analyzed by Spectroscopy %0 Journal Article %D 2020 %J SPECTROSCOPY AND SPECTRAL ANALYSIS %R 10.3964/j.issn.1000-0593(2020)12-3953-10 %P 3953-3962 %V 40 %N 12 %U {https://www.gpxygpfx.com/CN/abstract/article_11767.shtml} %8 2020-12-01 %X Glutamate decarboxylase (GAD) catalyzes an α-decarboxylation reaction of glutamate to produce γ-aminobutyric acid (GABA). Interestingly, two kinds of mung bean [Vigna radiate (L.)] GADs were firstly extracted and purified in this research. Two GADs in mung bean were both dimers with a molecular mass of 155 kDa (GAD1) and 75 kDa (GAD2). The enzymatic properties of GAD1 and GAD2 were detected in this research. Infrared spectroscopy analysis revealed that more higher-ordered structure contents, α-helix and β-sheet structures, was found in GAD2, which determined the higher stability of GAD2. It was analyzed by Raman that the molecular structures of GAD1 and GAD2 are generally “exposed”. Fluorescence analysis revealed that GAD1 had a more flexible and exposed molecular structure, while the conformation of GAD2 was more compact and conservative. It was found that pH and temperature-induced structural change decreased the enzyme activity. Ca2+ was involved in binding the calmodulin-binding domain of GADs and induced a “buried” and compact structure. The unfolding of GAD induced by SDS, impaired the enzyme activity. KI, MgSO4, AgNO3, and SDS significantly inhibited GAD1 and GAD2 activities. Tween 80, Ca2+ and Cu2+ could significantly activate GAD1 and GAD2, and Fe2+ only increased GAD2 activity.