Purine nucleotide cycle. Evidence for the occurrence of the cycle in brain.
Purine nucleotide cycle. Evidence for the occurrence of the cycle in brain.
复制标题
嘌呤核苷酸循环。
DOI：
10.1016/s0021-9258(17)33905-4
复制
发表时间：
1976
期刊：
影响因子：
--
通讯作者：
J. Lowenstein
中科院分区：
文献类型：
--
作者：
V. Schultz;J. Lowenstein
大鼠脑的无细胞提取物催化嘌呤核苷酸循环的反应。氨是在循环的脱氨阶段而不是胺化阶段形成的。大脑中腺苷酸脱氨酶的活性足以解释已报道的最大氨生成率。谷氨酸脱氢酶的活性不足以解释这些氨生成速率。腺苷琥珀酸合成酶和腺苷琥珀酸酶的活性几乎足以解释在大脑中观察到的氨产生的稳态速率。由于副反应的发生，尤其是由磷酸单酯酶、核苷磷酸化酶和胍酶催化的副反应，脑提取物中循环的证明变得复杂。
Cell-free extracts of rat brain catalyze the reactions of the purine nucleotide cycle. Ammonia is formed during the deamination but not the amination phase of the cycle. The activity of adenylate deaminase in brain is sufficient to account for the maximum rates of ammonia production that have been reported. The activity of glutamate dehydrogenase is not sufficient to account for these rates of ammonia production. The activities of adenylosuccinate synthetase and adenylosuccinase are nearly sufficient to account for the steady state rates of ammonia production observed in brain. Demonstration of the cycle in extracts of brain is complicated by the occurrence of side reactions, in particular those catalyzed by phosphomonoesterase, nucleoside phosphorylase, and guanase.