which is the sum of the interaction confidence scores of C q with its interactive compounds in the training dataset by counting both the number of interactive compounds and the interaction confidence scores. Obviously, the higher the score of Eq. 4, the more likely C q is to be involved in the j-th metabolic pathway C j . Thus, for a given query compound C q , we can use Eq. 4 to calculate its 11 scores, with each associated with one of the 11 metabolic pathway classes. The class to which the compound C q most likely belongs should be the one with the highest score. In other words, the query compound C q will be predicted to belong to the mth metabolic pathway class if m~arg max j S(C q [j)jj~1,2,:::,11