Hypoxanthine, a purine heterocyclic compound with N and O atoms, has capability to combine metal ions or adsorb on metals. By using density functional theory (DFT) method calculation, the energy, charge distribution, molecular orbital and vibration spectra information of tautomeric hypoxanthine were given. Combined with these DFT results, the influence of pH on the structure of tautomeric hypoxanthine was studied by surface enhanced Raman spectroscopy (SERS). Electrochemical SERS was applied to study the properties of hypoxanthine/gold interface. It is found that the structure of adsorbed hypoxanthine was changed from slightly tilted to upright with negatively moving of potentials. (C) 2015 Elsevier Ltd. All rights reserved.