Lane M J, Thomas G J
Biochemistry. 1979 Sep 4;18(18):3839-46. doi: 10.1021/bi00585a002.
Pseudo-first-order rate constants governing the deuterium exchange of 8-CH groups in guanosine 5'-monophosphate (5'-rGMP) and guanosine 3':5'-monophosphate (cGMP) were determined as a function of temperature in the range 30-80 degrees C by means of laser-Raman spectroscopy. For each guanine nucleotide the logarithm of the rate constant exhibits a strictly linear dependence on reciprocal temperature: i.e., k psi = Ae-Ea/RT with A = 8.84 X 10(14) h-1 and Ea = 24.6 kcal/mol for 5'-rGMP and A = 3.33 X 10(13) h-1 and Ea = 22.2 kcal/mol for cGMP. Exchange of the 8-CH groups in guanine nucleotides is generally 2-3 times more rapid than in adenine nucleotides [cf. g. j. thomas, Jr., & J. Livramento (1975) Biochemistry 14, 5210-5218]. As in the case of adenine nucleotides, cyclic and 5' nucleotides of guanine exchange at markedly different rates at lower temperatures, with exchange in the cyclic nucleotide being the more facile. Each of the guanine nucleotides was prepared in four different isotopic modifications for Raman spectral analysis. The Raman frequency shifts resulting from the various isotopic substitutions have been tabulated, and assignments have been given for most of the observed vibrational frequencies.
通过激光拉曼光谱法，测定了30至80摄氏度范围内鸟苷5'-单磷酸（5'-rGMP）和鸟苷3':5'-单磷酸（cGMP）中8-CH基团的氘交换的伪一级速率常数与温度的函数关系。对于每种鸟嘌呤核苷酸，速率常数的对数与绝对温度的倒数呈严格的线性关系：即，对于5'-rGMP，kψ = Ae-Ea/RT，其中A = 8.84×10(14) h-1，Ea = 24.6 kcal/mol；对于cGMP，A = 3.33×10(13) h-1，Ea = 22.2 kcal/mol。鸟嘌呤核苷酸中8-CH基团的交换通常比腺嘌呤核苷酸快2至3倍[参见G. J. Thomas, Jr.和J. Livramento（1975年），《生物化学》14, 5210 - 5218]。与腺嘌呤核苷酸的情况一样，鸟嘌呤的环核苷酸和5'核苷酸在较低温度下以明显不同的速率进行交换，环核苷酸中的交换更容易。每种鸟嘌呤核苷酸都制备了四种不同的同位素修饰用于拉曼光谱分析。已将各种同位素取代导致的拉曼频移制成表格，并对大多数观察到的振动频率进行了归属。
