MECHANISM AND CATALYSIS OF REACTIONS OF ACYL PPHOSPHATES .1. NUCLEOPHILIC REACTIONS
MECHANISM AND CATALYSIS OF REACTIONS OF ACYL PPHOSPHATES .1. NUCLEOPHILIC REACTIONS
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DOI：
10.1021/ja01482a024
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发表时间：
1961-01-01
影响因子：
15
通讯作者：
JENCKS, WP
中科院分区：
文献类型：
--
作者：
DISABATO, G;JENCKS, WP
酰基转移反应从乙酰磷酸到正丁胺，氨，甘氨酸和羟胺受到一般碱催化，如所示的一个大于一阶依赖性的浓度的胺缓冲液的速率。乙酰磷酸盐在中性pH下与羟胺、苯胺、吗啉、N-甲基咪唑、甘氨酸和甘氨酰甘氨酸的反应主要通过酸催化途径进行，即胺碱与乙酰磷酸单阴离子的反应。这些催化反应路径的存在部分地解释了乙酰磷酸相对高的反应性。钙离子对乙酰磷酸与甘氨酸的反应以及中性和碱性催化的水解都有催化作用。与吡啶，4-甲基吡啶，三亚乙基二胺和可能的三甲基胺的反应得到PO键断裂;在氟化物的存在下，形成氟磷酸盐，这表明这些反应代表磷酰基转移的亲核催化。氟离子也直接与乙酰磷酸单阴离子反应生成氟磷酸根，但不与乙酰磷酸二阴离子发生明显反应。乙酰咪唑在中性pH下的高反应性与其说是由于化合物本身的高反应性，不如说是由于其反应可用的易酸和一般的碱催化途径。2本研究旨在确定乙酰磷酸（另一种具有生物化学重要性的“富能”化合物）3-6在接近中性的水溶液中通过类似的催化途径进行反应的程度。在研究过程中，我们发现了几个意想不到的酰基磷酸反应的特征。
Acyl transferreactions from acetyl phosphate to ro-butylamine, ammonia, glycine and hydroxylamine are subject to general base catalysis, as shown by a greater than first-order dependence of the rate on the concentration of amine buffers. The re-actions of acetyl phosphate at neutral pH. with hydroxylamine, aniline, morpholine, N-methylimidazole, glycine and glycylglycine give C-0 bond breaking and proceed predominantly through an acid-catalyzed pathway; ie, they involve a reac-tion of amine base with the acetyl phosphate monoanion. The existence of these catalyzed reaction paths partially accounts for the relatively high reactivity of acetyl phosphate. The reaction with glycine and the neutral and base-catalyzed hydrolysis of acetyl phosphate are catalyzed by calcium ion. The reactions with pyridine, 4-methylpyridine, triethylenedi-amine and probably trimethylamine give PO bond breaking; in the presence of fluoride, fluorophosphate is formed, suggesting that these reactions represent nucleophilic catalysis of phosphoryl transfer. Fluoride also reacts directly withthe acetyl phosphate monoanion to give fluorophosphate, but does not react appreciably with the acetyl phosphate dianion.The high reactivity of acetylimidazole at neutral pH is due not so much to a high reactivity of the compound itself as to the availability of facile acidand general base-catalyzed paths for its reactions. 2 The present study was undertaken to determine the extent to which the reactions of acetyl phosphate, another “energy-rich” compound of some biochemical importance, 3-6 proceed by similar cata-lytic pathways in aqueous solution near neutrality. In the course of the study several unexpected characteristics of acyl phosphate reactions were en-countered.