Thermolysin structure co-crystallized with the V-K dipeptide (2tlx), and superimposed the results of experimental mapping, i.e., the ligand positions in structures solved in 10% isopropanol, 50% acetone, 50% acetonitrile, and 50 mM phenol. The color scheme used for the ligands is ochre, V-K dipeptide; red, isopropanol (IPA); blue, acetone (ACN); black, acetonitrile (CCN); and purple, phenol (IPH). For the protein side chains we use the standard atomic colors, i.e., carbon, grey; oxygen, red; nitrogen, blue; and hydrogen, white. All solvents bind in the S1’ pocket (IPA1, ACN1, CCN1, and IPH1), and isopropanol also binds at the S1 site (IPA5). The S1’ pocket is found to be the only location that binds all four probes (Site 1 in Table above), with additional clustering of isopropanol, phenol, and acetone close to the S1 subsite (Site 2 in Table above)