A NEW APPROACH TO TIME-RESOLVED STUDIES OF ATP-REQUIRING BIOLOGICAL-SYSTEMS - LASER FLASH-PHOTOLYSIS OF CAGED ATP
A NEW APPROACH TO TIME-RESOLVED STUDIES OF ATP-REQUIRING BIOLOGICAL-SYSTEMS - LASER FLASH-PHOTOLYSIS OF CAGED ATP
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DOI：
10.1073/pnas.77.12.7237
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发表时间：
1980-01-01
期刊：
影响因子：
--
通讯作者：
TRENTHAM, DR
中科院分区：
文献类型：
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作者：
MCCRAY, JA;HERBETTE, L;TRENTHAM, DR
2-硝基苄基衍生物是合成有机化学中有用的光不稳定保护基团。最近，合成了P3-1-(2-硝基)苯乙基腺苷5''-三磷酸笼ATP，并且其光解作用被证明可以原位产生ATP。该反应和相关反应对于完整和可溶性生物系统的结构和动力学研究具有巨大的潜力，因此定义光解反应的动力学特征非常重要。笼中的 ATP (2.5 mM) 在 347 nm 处被来自 25 mJ 能量的倍频红宝石激光器的单个 30 ns 脉冲光解，产生 500 μM ATP。整个反应的动力学是通过监测 ATP 诱导的[兔肌肉]肌动球蛋白解离的动力学来确定的，这是一种已知动力学特征的反应。 500μM ATP的释放由速率常数为2.2倍的过程控制。 109 [H+] s-1 在 22°C C在pH 5.8-9.5下，相当于在pH 7下220 s-1。这个过程被认为是酰硝基化合物的分解，这是根据其光谱特性和相关2-硝基苄基化合物的光致变色性来鉴定的。
2-Nitrobenzyl derivatives are useful photolabile protecting groups in synthetic organic chemistry. Recently, P3-1-(2-nitro)phenylethyladenosine 5''-triphosphate caged ATP, was synthesized and its photolysis was shown to generate ATP in situ. This and related reactions have great potential for structural and kinetic studies of both intact and soluble biological systems and it is thus important to define the kinetic characteristics of the photolytic reaction. Caged ATP (2.5 mM) was photolyzed at 347 nm by a single 30 ns pulse from a frequency-doubled ruby laser of 25 mJ energy to generate 500 .mu.M ATP. The kinetics of the overall reaction were determined by monitoring the kinetics of ATP-induced dissociation of [rabbit muscle] actomyosin, a reaction of known kinetic characteristics. Release of 500 .mu.M ATP was controlled by a process having a rate constant of 2.2 .times. 109 [H+] s-1 at 22.degree. C at pH 5.8-9.5, which corresponds to 220 s-1 at pH 7. This process is believed to be the breakdown of an aci-nitro compound, which was identified on the basis of its spectral properties and the photochromicity of related 2-nitrobenzyl compounds.