For the four scoring functions (i.e., Ligscore1, Ligscore2, PLP1 and PLP2), Table 2 exhibited a high correlation between any two of them. The correlation was higher for LigScore and PLP (R = 0.97,0.98) because they belong to the empirical scoring function category and the sum of the pairwise linear potentials between the ligand and the protein heavy atoms with parameters is dependent on the interaction type.