Purification and characterization of alcohol dehydrogenase (ADH) from Gluconobacter suboxydans was done in order to biotechnological and industrial application. Solubilization of enzyme from bacterial membrane fraction by Triton X-100 and subsequent fractionation on DEAE-Sephadex A-50 and Hydroxyapatite was successful in enzyme purification. Enzyme assay reaction mixture contained potassium ferricyanide 0.1 M, McIlvaine buffer 0.1 M (pH 5.5), Triton X-100 10%, ethanol 1 M and enzyme solution. The purified ADH Optimum pH activity was 5.5. The enzyme was in maximum stability in pH 5.8. The substrate specificity of the enzyme was determined using the same enzyme assay method as described above, except that various substrates (100 mM) were used instead of ethanol. The relative activity of the ADH for ethanol was higher than the others. The effects of metal ions and inhibitors on the activity of the enzyme were examined by measuring the activity using the same assay method as described above. Activity of purified enzyme was increased in the presence of Ca(+2) and was decreased in presence the of ethylenediamine tetra acetic acid (EDTA). Because the proper structure and function of the enzyme is related to structural Ca(+2) and EDTA can chelate Ca(+2). An apparent Michaelis constant for ethanol were examined to be 1.7 x 10(-3) M for ethanol as substrate.