The authors state that the zinc-binding group and hydrophobic core of the inhibitor have weak ...The authors state that the zinc-binding group and hydrophobic core of the inhibitor have weak density in the binding pocket of ENPP1. The piperidinyl linker moiety shows very weak density apparently because of high flexibility of the hydrocarbon and it being exposed to the solvent. In polypeptide chain A the inhibitor was modeled with 0.5 occupancy. Trace of inhibitor in the electron density appears to be present in polypeptide B chain but the density is very weak and the inhibitor wasn't modeled there.