生物大分子波谱学原理 吴季辉 0.6 TOCSY 0.2 0.0 0.6 0.4 ( 0.2 0.0 0 50 100 150 200 250 tm(ms) FIGURE 6.44 Variation of cross-peak intensity as a function of isotropic mixing time for an isoleucine spin system.(a)Cross-peak intensity for transfer from the H spin with the HN spin removed and(b)cross-peak intensity for magnetization transfer from the HN spin.The curves for the destination spins are ( H,(---)H8,(-...-)Hy,(-.-)Hy2,and (----)H5.The transfer functions were calculated using the following coupling constants:HN=10.0 Hz,and J=12 Hz.Vicinal couplings to methyl groups were 6.7 Hz,all geminal couplings were-15 Hz,and all other vicinal couplings were 7 Hz.The effect of relaxation during the mixing was not considered. TOCSY 生物大分子波谱学原理 吴季辉