Abstract: ¹H spin system identifications of amino acid residues are the bases of investigation of structrue, function and motion of proteins by use of NMR techniques. 2D DQ-spectrum is an important method for the identification. 500 MHz and 300 MHz phase sensitive 2D DQ-spectra of Des-(B₂₆-B₃₀)-insulin in H₂O and S-sulfonated insulin A chain in D₂O were measured respectively. From their direct, remote and equivalence cross-peaks, the spin system identifications of various residues were carried out which confirmed the identifications from the COSY spectra and provided more information for the identification.

Key words: 2D-NMR, DQ-spectrum, insulin