Figure 2.

(a) Conventional two-dimensional ET–NOESY of the LDH⋅NAD⁺ complex, recorded with a mixing time τ_m = 150 ms. Relevant NAD⁺ protons are labeled with ADE for adenosine and NIC for nicotinamide. (b) Strip from the ET-NOESY spectrum of a shown with lower contours. (c) Corresponding strip from a QUIET–ET–NOESY spectrum recorded under identical conditions. Doubly selective inversion was achieved by applying a 12-ms cosine-modulated Gaussian cascade Q³ in the middle of the mixing time to invert two frequency bands (represented by dashed lines), each of ≈1.1 ppm width, centered around 6.07 ppm (to invert H1′^ADE of the adenosine) and 8.36 ppm (to invert both adenosine protons H2^ADE at 8.13 ppm and H8^ADE at 8.47 ppm). No water suppression methods were used.