Interactions of Cyclic Peptides with Aromatic Compounds

Dipole Interactions of Cyclic Peptides with Aromatic Compounds 

On the other hand, the addition of benzene to the chloroform solution of Cyclo-(Sar2) and Cyclo-(Sar ly) caused upfield shifts of N-CH3 and C H2 resonance signals (77), although these cyclic peptides only have a cis peptide bond. The upfield shift implies the complex formation between the tyclic peptides and benzene. However, this complex may have been formed due to a dipole-induced dipole interaction, the latter being generated in benzene by the action of a strong dipole of cyclic peptides. A/[benzene], in which A represents the benzene-induced drift in ppm, was 

Amide Solvent Temp. °C As.sociation constant (mol amide/kg soln) (mol frac) Ref. 

Torchia and Deber (76) observed an extensive nonlinear drift of the resonance signal of Cyclo-(Pro3) in CD2Q2 when was added, and concluded the forma- 

Charge-transfer Interactions of Cyclic Peptides widi Iodine 

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