Matsumoto S S, Raivio K O, Seegmiller J E
J Biol Chem. 1979 Sep 25;254(18):8956-62.
Adenine nucleotide breakdown to nucleosides and purine bases was measured in cultures of human lymphoblastoid cells following: 1) the inhibition of oxidative phosphorylation in the absence of glucose or 2) the addition of 2-deoxyglucose. A mutant cell line, deficient in adenosine kinase, in the presence of an adenosine deaminase inhibitor was used to measure utilization of the two pathways of AMP catabolism involving initial action of either purine 5'-nucleotidase or AMP deaminase. In such a system the appearance of adenosine induced by the oxidative phosphorylation inhibitor, rotenone, implies that approximately 70% of AMP breakdown occurs via dephosphorylation. By the same method, deamination accounts for 82% of AMP breakdown when 2-deoxyglucose is added. The occurrence of AMP dephosphorylation is not correlated with elevated concentrations of substrate or with decreased concentrations of the inhibitors of 5'-nucleotidase, ATP and ADP. Dephosphorylation occurs if, and only if, the adenylate energy charge decreases to about 0.6 in these experiments. In cultures deprived of glucose and oxygen, adenine nucleotide degradation via dephosphorylation results in recovery of normal energy charge values.
在以下情况下，对人淋巴母细胞培养物中腺嘌呤核苷酸分解为核苷和嘌呤碱的过程进行了测定：1）在无葡萄糖的情况下抑制氧化磷酸化；2）添加2-脱氧葡萄糖。使用一种缺乏腺苷激酶的突变细胞系，在腺苷脱氨酶抑制剂存在的情况下，来测定涉及嘌呤5'-核苷酸酶或AMP脱氨酶初始作用的AMP分解代谢的两条途径的利用情况。在这样一个系统中，氧化磷酸化抑制剂鱼藤酮诱导产生的腺苷表明，大约70%的AMP分解是通过去磷酸化发生的。通过同样的方法，当添加2-脱氧葡萄糖时，脱氨基作用占AMP分解的82%。AMP去磷酸化的发生与底物浓度升高或5'-核苷酸酶抑制剂ATP和ADP浓度降低无关。在这些实验中，只有当腺苷酸能荷降至约0.6时，才会发生去磷酸化。在缺乏葡萄糖和氧气的培养物中，通过去磷酸化进行的腺嘌呤核苷酸降解导致能量电荷值恢复正常。
