STUDIES IN SULFATE ESTERS .5. MECHANISM OF HYDROLYSIS OF PHENYL PHOSPHOSULFATE A MODEL SYSTEM FOR 3'-PHOSPHOADENOSINE 5'-PHOSPHOSULFATE
STUDIES IN SULFATE ESTERS .5. MECHANISM OF HYDROLYSIS OF PHENYL PHOSPHOSULFATE A MODEL SYSTEM FOR 3'-PHOSPHOADENOSINE 5'-PHOSPHOSULFATE
复制标题
DOI：
10.1021/ja00719a034
复制
发表时间：
1970-01-01
影响因子：
15
通讯作者：
HEVEY, RC
中科院分区：
文献类型：
--
作者：
BENKOVIC, SJ;HEVEY, RC
以3‘-磷酸腺苷-5’-磷酸-硫酸盐(PAPS)和腺苷-5‘-磷酸-硫酸盐为模型合成了苯基硫代磷酸酯。类似物非酶水解的pH-速率曲线表明，双阴离子和单阴离子是不稳定的。单阴离子的水解被认为是酸催化的单分子机理，基于占主导地位的SO键断裂、As*的小负值、单阴离子在乙醇-水混合溶剂中的硫酸化性质以及典型的铝机理的氧化重水溶剂同位素效应而消除了三氧化硫。并与乙酰硫酸盐的反应机理进行了比较，以揭示硫代磷键的独特性质。3‘-磷酸腺苷-5’-磷酸硫酸盐(PAPS)作为硫酸盐供体在形成黄精硫酸盐、脑硫脂和酚硫酸盐的过程中的重要性得到了很好的证实。1-3PAPs和腺苷5‘-磷酸硫酸盐(APS)也被证明在还原
Phenyl phosphosulfatehas been synthesized as a model for 3'-phosphoadenosine 5'-phosphosulfate (PAPS) and adenosine 5'-phosphosulfate. The pH-rate profile for the nonenzymic hydrolysis of the analog indicates the dianion and monoanion to be hydrolytically labile. Hydrolysis of the monoanion is viewed as an acid-catalyzed unimolecular mechanism with elimination of sulfur trioxide on the basis of predominant SO bond cleavage, the small negative value of AS*, the sulfating properties of the monoanionin mixed alcohol-water solvents, and a deuterium oxide solvent isotope effect typical of an Al mechanism. A comparison with the mech-anistic mode of hydrolysis of acetyl sulfate is developed in order to delineate the unique characteristics of the phos-phosulfate bond. These results are interpreted with regard to the significance of the structure which evolved biologically to transport active sulfate.The importance of 3'-phosphoadenosine 5'-phosphosulfate (PAPS) as the sulfate donor in the formation of chrondrointin sulfate, cerebrosulfatides, and phenolic sulfates is well established. 1-3 PAPS and adenosine 5'-phosphosulfate (APS) have also been shown to act as intermediates in the reduction of