Anomalous oxygen-18 exchange during ATP synthesis in oxidative phosphorylation.
Anomalous oxygen-18 exchange during ATP synthesis in oxidative phosphorylation.
复制标题
氧化磷酸化中 ATP 合成过程中的异常氧 18 交换。
DOI：
10.1021/bi00368a047
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发表时间：
1986
期刊：
影响因子：
2.9
通讯作者：
Hackney,DD
中科院分区：
文献类型：
--
作者：
Sines,JJ;Hackney,DD
Jacqueline J.Sines和David D.Hackney*生物科学系，卡内基-梅隆大学，匹兹堡，宾夕法尼亚州，15213收到1986年4月2日；修订手稿收到1986年5月8日摘要：由琥珀酸氧化驱动的亚线粒体颗粒从高度浓缩的[180]P合成三磷酸腺苷产生180标记三磷酸腺苷物种的分布，偏离了由简单的交换模型预测的分布。对照实验表明，当结合在亚线粒体颗粒上的[LSO]ADP通过腺苷酸激酶合成时，[LSO]ATP的同位素分布没有变化。由于ATP合成的多条途径，观察到的偏差与异质性产生的偏差是相反的。有两种复杂的模型可以解释观察到的偏差。一种模型在交换反应中具有不等价的P氧基，这是由于在结合的ATP的可逆循环中P氧基的不完全游程。另一种模型假设，在每一次交易中，高交换路径和低交换路径之间必须发生缓慢的转换。对水和磷酸盐之间标记氧原子交换反应的分析已被证明是对许多合成或水解磷酸酯的酶的机理的重要探索。方案一的简单合成模型说明了在这种反应产物中经常观察到的多种水氧的可能来源。如果ATP是在未浓缩的水中从P合成的，那么所有四个f都得到了美国公共卫生服务的赠款AM25980和博士前培训补助金GM08067(对JJS)的支持，并得到了美国心脏协会(对DDH)的已建立的研究。初步工作已被报告(Hackney，1983)。
Jacqueline J. Sines and David D. Hackney* Department of Biological Sciences, Carnegie-Mellon University, Pittsburgh, Pennsylvania 15213 Received April 2, 1986; Revised Manuscript Received May 8, 1986 abstract: The synthesis of ATP from highly enriched [180] P¡ by submitochondrial particles driven by succinate oxidation produces distributions of 180-labeled ATP species that deviate from the distributions predicted by a simple model for the exchange. Control experiments indicate no change in isotopic distribution when [lsO] ATP is synthesized from [lsO] ADP byadenylate kinase, which is bound to the submitochondrial particles. The observed deviations are in the opposite direction from that produced by heterogeneity due to multiple pathways for ATP synthesis. Two types of complex models can account for the observed deviations. One model has nonequivalence of the P¡ oxygens during theexchange reaction, due to incomplete ran-domization of the P¡ oxygens during the reversible cycles of hydrolysis and synthesis of bound ATP. The other model assumes that, during each turnover, a slow transition must occur between a high-exchange and a low-exchange pathway..^^. nalysis of the exchange reactions of labeled oxygen atoms between water and phosphate has proven to be an important probe of the mechanisms of a number of enzymes that synthesize or hydrolyze phosphoesters.[See Mitchell (1984) for a recent review.] The simple synthesis model of Scheme I illustrates the probable source of the multiple water oxygens often observed in the products of such reactions. If ATP is synthesized in unenriched water from P¡ that has all four f Supported by Grant AM25980 and Predoctoral Training Grant GM08067 (to JJS) from the US Public Health Serviceand an Es-tablished Investigatorship from the American Heart Association (to DDH). Preliminary work has been reported (Hackney, 1983).