All-atom molecular dynamics (MD) simulations for a single molecule of met-enkephalin in aqueous solution have been used to study the solvent structure surrounding the hydrated penta-peptide. The hydrophobicity (or hydrophicility) of the individual met-enkephalin atoms is analyzed in terms of the solute-solvent, site-site radial distribution functions g(AB)(r) that are computed for the all possible AB atom pairs. The MD simulated g(AB)(r) are also used for testing the reference interaction site model theory calculations by Hirata and co-workers for the same system. (C) 2003 American Institute of Physics.