Figure 1: Adjustments made on Kuhn, Schmitt and Klebe’s method. For both A and B: 1 - Represents the van der Waals surface. 2 - Represents the molecular surface (skin surface). The sphere 3 represents the local map. Two vectors, v and p, define the exposure of a particular physicochemical property. The standard vector v represents the mean direction of the physicochemical property exposure, herein the acceptor property. Instead of use vector r as a normalized summation of all vectors pointing to the surface grid, vector p was used. The vector p is defined by the point of greatest electrostatic potential on the skin surface inside the sphere 3 region. Cut-off values to β angle between v and p were the same used by Kuhn, Schmitt and Klebe’s method for the vectors v and r. For instance, in A the molecular surface approximates to the van der Waals surface and the value of β is small, while in B the molecular surface moves away from the van der Waals surface and the value of β is large. Therefore, it was considered that the larger the exposed area and the smaller the β angle, the better to atoms establish hydrogen bonds. The acceptor vary from 0 to 10 A2.