吲哚满二酮（异吲哚酮）在pH 5.0条件下对兔小肠刷状缘蔗糖酶的抑制作用。
Inhibition of rabbit intestinal brush border sucrase by indolin 2,3-dione (isatin) at pH 5.0.
作者信息
Gargari M L, Siddiqui U, Bansal R C, Singh K, Mahmood A
机构信息
Department of Biochemistry, Panjab University, Chandigarh.
出版信息
Indian J Biochem Biophys. 1994 Jun;31(3):191-4.
Isatin (10 mM) inhibited the activity of rabbit brush border sucrase by 60% at pH 5.0 but it had no effect on enzyme activity around neutral pH. Isatin inhibition of sucrase was unaffected by Na+ ions but K+ and Cs+ ions reduced enzyme inhibition, partially. Kinetic analysis revealed that sucrase inhibition by isatin at acidic pH was non-competitive with Ki of the order 6.5-7.8 mM. Isatin together with 4 mM harmaline or iodoacetate (3 mM) or dithionitrobenzene (2 mM) yielded 80-85% inhibition of the enzyme. These observations suggest that inhibitory sites for isatin, harmaline and -SH group reacting agents are distinct in rabbit brush border sucrase.
异吲哚酮（10 mM）在pH 5.0时可抑制兔刷状缘蔗糖酶活性60%，但在接近中性pH值时对酶活性无影响。异吲哚酮对蔗糖酶的抑制作用不受Na⁺离子影响，但K⁺和Cs⁺离子可部分降低酶的抑制作用。动力学分析表明，在酸性pH条件下，异吲哚酮对蔗糖酶的抑制作用为非竞争性抑制，抑制常数Ki约为6.5 - 7.8 mM。异吲哚酮与4 mM骆驼蓬碱或碘乙酸（3 mM）或二硫代硝基苯（2 mM）共同作用时，可对该酶产生80 - 85%的抑制作用。这些观察结果表明，异吲哚酮、骆驼蓬碱和-SH基团反应剂在兔刷状缘蔗糖酶上的抑制位点是不同的。
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