Sialic acid-binding lectin recognizing oligosaccharides containing terminal sialic acid linked via alpha-2,3 bond to penultimate galactose residues (PubMed:3350806). Binds the trisaccharide sequence Neu5Ac-alpha-2,3-Gal-beta-1,4-GlcNAc (PubMed:1985926). Binds fetuin when fully glycosylated but not when the high mannose-type glycans are removed, although the secondary structure is virtually unaffected by deglycosylation of the high mannose-type glycans (PubMed:26003537). The lectin activity may depend on the presence of a single GlcNAc attached to N-90 (PubMed:26003537). Homodimer; disulfide-linked (PubMed:9163528, PubMed:27720757). Dimer of homodimers (PubMed:10747930). The glycosylation on N-90 is determined to by of the high mannose type in PubMed:26003537, while PubMed:27720757 found a paucimannose at this position. Processed at its C-terminus. Belongs to the leguminous lectin family.