Molecular dynamics simulations have been used to investigate the dynamics of hydrogen bonds (HBs) formed by hydration water in selected hydrophilic and hydrophobic biomolecules. Labelling all of atoms in the molecule allows analysing the HB relaxation time at specific donor and acceptor binding sites. The results show that the water-water HBs present a longer relaxation time around the completely hydrophilic peptide, and that the water-biomolecule HBs exhibit a distinct behaviour depending on the binding sites at the hydrophilic or hydrophobic bio-interface. The presence of a large hydrophobic surface enhances, in particular at low temperature, the dynamical heterogeneity in the neighbouring hydrogen bond network. (C) 2011 Elsevier B.V. All rights reserved.