Rapid purification of human placental aldose reductase

Aldose reductase (alditol:NADP oxidoreductase EC 1.1.1.21) an enzyme in the polyol pathway which has been implicated in the pathogenesis of diabetic complications has been purified from the human placenta. Using affinity chromatography the enzyme can be obtained with apparent homogeneity in three steps. An initial 30-70% ammonium sulfate fraction was placed on a 4-carboxybenzaldehyde-coupled AH-Sepharose 4B column where upon elution with 0.1 m Na,K-phosphate buffer, pH 6.2, an enzyme fraction separated from the major protein peak. Chromatography of this enzyme fraction on an Amicon Matrex Orange A dyeligand column and elution with phosphate buffer containing 0.1 mm NADPH yielded aldose reductase of high purity. Antibodies raised in rabbits against the purified enzyme gave an apparent single line of identity with cither crude or purified aldose reductase.