Isolated from the cultivated banana Musa paradisiaca, banana lectin (BanLec) is a very stable mannose- and glucose-binding lectin consisting of two identical 15 kDa subunits and a reported isoelectric point of pH 7.3. Although structurally related to the Jacalin family of lectins, BanLec recognizes internal α(1,3) glucosyl- and mannosyl- residues and has also been reported to bind β(1,3) and β(1,6) glucosyl-structures.
Like Galanthus nivalis lectin, BanLec has been shown to bind gp120 glycoprotein, an important envelope component of the human immunodeficiency virus (HIV-1), and to strongly inhibit HIV-1 entry into cells. Glycoproteins on the surface of other viruses are also likely to be recognizable by BanLec. This lectin has been reported to be a potent mitogen for peripheral T-cells in the presence of interleukin-2, and appears likely to be a cause of allergic reaction to bananas, since IgG4 antibodies against BanLec have been detected in humans.