Fig. 1

Schematic illustration of look-up table construction (PROXIMAL step 1). a A CYP reaction transforms the drug antipyrine to 3-hydroxymethylantipyrine, both represented in KEGG atom type format. Red, blue and green atoms are the reaction centers, adjacent neighbors and distant neighbors, respectively. The .mol files were downloaded from DrugBank. b List of matched atoms for the reactant and product. c The transformation look-up table has two parts, consisting of a key that specifies the modified reactant substructure and a corresponding value that describes the modifications resulting in the product