Molecular dynamics simulations and 2D-NOESY spectroscopy were applied to study the conformations and hydrogen-bonding interactions of ACE-inhibitory tripeptide Gly-Glu-Phe (GEF) in aqueous and DMSO solutions. The properties of GEF in simulations were characterized by intramolecular distance, root-mean-square deviation, solvent-accessible surface, and radius of gyration. Interestingly, the GEF molecule showed different behavior in different solvents. In aqueous solution, the GEF was highly flexible, and it could quickly convert from extended state to folded state. However, in DMSO solution, the extended conformations were hardly observed. The GEF molecule preferred extended state in aqueous compared to DMSO solution, which was confirmed by 2D-NOESY. [ABSTRACT FROM AUTHOR]