Marchal J P, Canet D
Biochemistry. 1980 Apr 1;19(7):1301-4. doi: 10.1021/bi00548a006.
An indirect method combining double-resonance and difference spectroscopy has been used in order to determine 15N chemical shifts and 1J15N1H in glutathione (in H2O at pH 3 and under the same conditions with urea added) and in a series of tripeptides of the type Gly-Gly-L-X (with X = Glu, His, Val, Leu, and Ile) in H2O and at two different pH values. This method has proved to be very efficient as long as the NH proton is not in exchange. The chemical shifts are shown to depend on the considered sequence and especially on the substituent in the gamma position. One-bond couplings show some systematic trends which have been tentatively interpreted in terms of the s character of the N-H bond. Although these latter parameters seem of potential utility in structural determinations, additional data will be needed in order to rationalize their variations.
一种结合双共振和差示光谱的间接方法已被用于测定谷胱甘肽（在pH 3的水中以及添加尿素的相同条件下）以及一系列Gly-Gly-L-X型三肽（X = Glu、His、Val、Leu和Ile）在水中和两个不同pH值下的15N化学位移和1J15N1H。只要NH质子不发生交换，该方法就被证明非常有效。结果表明，化学位移取决于所考虑的序列，尤其取决于γ位的取代基。一键耦合显示出一些系统趋势，已尝试根据N-H键的s特性进行解释。尽管后述这些参数在结构测定中似乎具有潜在用途，但仍需要更多数据来合理化它们的变化。
