Production and purification of a recombinant human 14 kDa β‐galactoside‐binding lectin

The cDNA for a 14 kDa human beta-galactoside-binding lectin was inserted into a plasmid carrying a taq promoter, and the lectin protein was expressed in E. coli cells. The recombinant lectin was extracted from the cells and purified to apparent homogeneity by a single-step chromatography on an asialofetuin-agarose column. Subunit molecular mass (14 kDa), hemagglutinating activity and antigenicity were indistinguishable from those of the human placental lectin. Though the N-terminal of the placental lectin is blocked with an acetyl group, the recombinant lectin was found to have a free amino group. However, the N-terminal amino acid sequences were identical. The recombinant lectin was considered to have the same three-dimensional structure as the placental lectin.