PURIFICATION AND CHARACTERIZATION OF A POD LECTIN FROM GREAT NORTHERNBEAN, PHASEOLUS-VULGARIS L

The pods of the Great Northern bean plant contain a lectin (GN(p)L) th at highly resembles seed lectins (GNLs) of the same plant. Purificatio n of GN(p)L from pod extracts was achieved by ion-exchange chromatogra phies on CM- and DEAE-celluloses and gel filtration chromatography on Sephacryl S-300 HR. GN(p)L has a similar SDS-PAGE pattern to that of G NLs. GN(p)L and GNLs yield three subunits though each GN(p)L subunit i s 0.5 kDa smaller than the corresponding GNLs subunit (GN(p)L; pod-alp ha-subunit of 34.0 kDa, pod-beta-subunit of 36.5 kDa, and pod-gamma-su bunit of 38.5 kDa). GN(p)L and GNLs display indistinguishable carbohyd rate specificities and have similar amino acid compositions. Pod-alpha -subunit cross-reacts with antibodies against GNLs on western blotting . On the other hand, the N-terminal amino acid sequence of pod-alpha-s ubunit suggests that GN(p)L is a distinct gene product from those of G NLs genes although they are shown to be homologous proteins.