An SDS-PAGE analysis showing the various stages of purification of nr-G3PDH from celery leaves. Lane M, Molecular mass standards (Bio-Rad Laboratories, broad range); lane 1, after acetone precipitation (20 μg); lane 2, pooled active fractions from a DEAE-Sepharose column (20 μg); lane 3, pooled active fractions from a Sephadex-200 column (20 μg); lane 4, pooled active fractions from an Affi-Blue Sepharose column (20 μg). Proteins were stained with Coomassie Blue. Molecular mass of nr-G3PDH is indicated on the right side of the gel as 53 kD.