碱性磷酸酶对嘌呤单核苷酸的去磷酸化作用。底物特异性和抑制模式。
Dephosphorylation of purine mononucleotides by alkaline phosphatases. Substrate specificity and inhibition patterns.
作者信息
Jensen M H
出版信息
Biochim Biophys Acta. 1979 Nov 9;571(1):55-62. doi: 10.1016/0005-2744(79)90224-9.
Three purine mononucleotides, adenosine-, inosine- and guanosine monophosphate, were used as substrates at pH 7.4 and at 10.4 for three alkaline phosphatases (orthophosphoric-monoester phosphohydrolase (acid optimum), EC 3.1.3.1) containing similar phosphate-binding serine groups at their esteratic sites. Substrate specificity was found for the enzymes from calf intestine and bovine liver. Alkaline phosphatase from Escherichia coli was nonspecific. A substrate-dependent and pronounced inhibition with the purine analogue 1,3-dimethyl xanthine was found for the enzymes from intestine and liver, but not for alkaline phosphatase from E. coli. A substrate-independent and pronounced inhibition was found for all three enzymes with the phosphomonoester p-nitrophenol phosphate as the inhibitor. Alkaline phosphatases may play an important role in the regulation of the intracellular content of purine mononucleotides.
在pH 7.4和10.4条件下，使用三种嘌呤单核苷酸，即腺苷酸、肌苷酸和鸟苷酸，作为三种碱性磷酸酶（正磷酸单酯磷酸水解酶（最适酸性），EC 3.1.3.1）的底物，这三种酶在其酯酶活性位点含有相似的磷酸结合丝氨酸基团。发现来自小牛肠和牛肝的酶具有底物特异性。来自大肠杆菌的碱性磷酸酶没有特异性。发现来自肠和肝的酶对嘌呤类似物1,3 - 二甲基黄嘌呤有底物依赖性且明显的抑制作用，但对来自大肠杆菌的碱性磷酸酶没有这种作用。以磷酸单酯对硝基苯酚磷酸作为抑制剂时，发现对所有三种酶都有底物非依赖性且明显的抑制作用。碱性磷酸酶可能在嘌呤单核苷酸细胞内含量的调节中起重要作用。
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