Schauenstein E, Saenger W, Schaur R J, Desoye G, Schreibmayer W
Z Naturforsch C Biosci. 1980 Jan-Feb;35(1-2):76-9.
Assuming a reversible equilibrium of an unfolded and a base-stacked conformation of both NADH and NAD+ the influence of pH, temperature and methanol on this equilibrium was studied as indicated by the UV-absorption of the adenine, band at 260 nm. By the addition of methanol as well as by an increase of temperature the equilibrium is shifted to the unfolded conformation. An increase of the H+ concentration seems to favor the unfolded conformation in the case of NAD+ while for NADH a decrease of the absorption coefficient is pointing to a higher percentage of the stacked conformation at lower pH. From the temperature variation of the absorption coefficients the enthalpies for the conformational change were calculated and compared with data obtained by different methods.
假设NADH和NAD⁺的未折叠构象与碱基堆积构象之间存在可逆平衡，如260nm处腺嘌呤的紫外吸收所示，研究了pH、温度和甲醇对该平衡的影响。通过添加甲醇以及升高温度，平衡向未折叠构象移动。H⁺浓度的增加似乎有利于NAD⁺的未折叠构象，而对于NADH，吸收系数的降低表明在较低pH下堆积构象的比例更高。根据吸收系数的温度变化计算了构象变化的焓，并与通过不同方法获得的数据进行了比较。
