Crotalaria juncea lectin (CJL) is isolated from Sunn hemp seeds. Sunn hemp is cultivated as a green fertilizer crop in a rotation cycle to improve soil conditions, help control of erosion, suppress weeds and reduce soil nematodes.

CJL has a molecular weight of 124 kDa and is composed of four identical polypeptide chains of 31 kDa. Similar to a number of other lectins, its composition is marked by a high content of acidic and hydroxylic amino acids and absence of sulfur-containing residues. The lectin has non-specific blood group activity. It displays specificity toward ß-galactosides and interacts with serum glycoproteins, cytochrome b5 and virus surface glycoproteins such as BVDV, influenza and bovine diarrhea.