Sodium dodecyl sulfate-polyacrylamide gel electrophoresis gel showing purification of the His-tagged YneI and GabD dehydrogenases. Lanes M, molecular weight marker; lane 1, wash fraction of nonspecific bound cell protein from GabD overexpression; lane 2, elution fraction containing purified GabD (predicted molecular mass of the monomer, 51.7 kDa); lane, 3, wash fraction of nonspecific bound cell protein from YneI overexpression; lane 4, elution fraction containing purified YneI (predicted molecular mass of the monomer, 49.7 kDa).