Hydrogen bonding between thrombin and the bound peptide.

In addition to P1-S1 interactions, also P6-S6 interactions rely on hydrogen bonding. The relatively specific S2 pocket does not show any hydrogen bonding at all.除P1-S1相互作用外，P6-S6相互作用同样依赖氢键（hydrogen bonding）。特异性相对较强的S2口袋则完全未呈现任何氢键相互作用。