With eight different scoring functions, Terp et al. docked a set of known inhibitors to three different matrix metalloproteases. They obtained scores analyzed using PCA and partial least-squares methods (PLS) [79] . The regression model they built has a good q 2 for predicting the activity of active compounds. The major difference between the present work and the work performed by Terp et al. is that we performed structure-based virtual screening on both active and inactive compounds. Terp et al. included only known inhibitors to quantitatively predict the binding affinity.