Purification and characterization of lens galectin-3. (A) SDS-PAGE and Western blot documentation of the purification process. Lane 1: Molecular weight markers. Lane 2: Crude lens fiber cell membranes. Lane3 and 4: Insoluble and soluble fractions, respectively, after treatment with 20 mM NaOH. Lane 5: Pure galectin-3 eluted from the α-lactose-agarose column with 100 mM lactose. Lane 6: Galectin-3 eluted from a size exclusion chromatography column S-75. Lanes 7 and 8: Immunoblot of the preparations in lanes 4 and 5 identifying galectin-3. (B) Galectin-3 bound to an α-lactose-agarose column, and was eluted with 100 mM lactose. (C) Size exclusion chromatography of the pure galectin-3. The protein was eluted at 12.5 ml. mAU refers to absorbance units at 280 nm (D) Calibration of the S-75 column. Vo = 8.3 ml. Galectin-3 has an apparent molecular mass of 22 kDa (arrow).