Grossfeld R M, Yancey S W, Baxter C F
Neurochem Res. 1984 Jul;9(7):947-63. doi: 10.1007/BF00964526.
Crayfish glutamic acid decarboxylase (GAD), like the homologous enzymes from other species, is inhibited by carbonyl-trapping agents (e.g. aminooxyacetic acid; AOAA) and sulfhydryl reagents (e.g. 5,5'-dithiobis-(2-nitrobenzoic acid); DTNB). It also is inhibited by the product GABA, many anions (e.g. SCN- and Cl-), and some cations (e.g. Zn+2). The inhibition by AOAA, but not that by DTNB, was prevented by increasing the concentration of the pyridoxal phosphate (PLP) coenzyme. GABA blocked the effects of PLP on enzyme activity. The inhibition by AOAA, DTNB, GABA, and chloride all were competitive with substrate. The effect of GABA occurs at physiological concentrations and may contribute to the regulation of GAD activity in vivo. The quantitative effect of anions is dependent on the cation with which they are administered. ATP stimulated GAD activity in homogenates prepared with potassium phosphate or Tris-acetate buffer, even when no exogenous PLP was provided.
小龙虾谷氨酸脱羧酶（GAD）与其他物种的同源酶一样，受到羰基捕获剂（如氨氧基乙酸；AOAA）和巯基试剂（如5,5'-二硫代双（2-硝基苯甲酸）；DTNB）的抑制。它还受到产物γ-氨基丁酸（GABA）、许多阴离子（如硫氰酸根离子和氯离子）以及一些阳离子（如锌离子）的抑制。增加磷酸吡哆醛（PLP）辅酶的浓度可防止AOAA的抑制作用，但不能防止DTNB的抑制作用。GABA阻断了PLP对酶活性的影响。AOAA、DTNB、GABA和氯离子的抑制作用均与底物存在竞争性。GABA在生理浓度下即可产生作用，可能有助于体内GAD活性的调节。阴离子的定量作用取决于与之同时给予的阳离子。即使未提供外源PLP，ATP也能刺激用磷酸钾或Tris-乙酸缓冲液制备的匀浆中的GAD活性。
