title: Musa acuminata (Del Monte banana) lectin is a fructose-binding lectin with cytokine-inducing activity.
abstract: A homodimeric, fructose-binding lectin was isolated from Del Monte bananas by using a protocol that involved ion-exchange chromatography on DEAE-cellulose and SP-Sepharose, and gel filtration by fast protein liquid chromatography on Superdex 75. Not only fructose, but also glucose, mannose, rhamnose and glucosamine could inhibit the lectin. The N-terminal amino acid sequence of its identical 15-kDa subunits was similar to lectins from other Musa species except for the deletion of the N-terminal glycine residue in Del Monte banana lectin. The hemagglutinating activity was stable up to 80 degrees C and also stable in the range pH 1-13. However, the hemagglutinating activity dwindled to an undetectable level at 90 degrees C. The lectin was capable of eliciting a mitogenic response in murine splenocytes and inducing the expression of the cytokines interferon-gamma, tumor necrosis factor-alpha, and interleukin-2 in splenocytes. The lectin also inhibited proliferation of leukemia (L1210) cells and hepatoma (HepG2) cells and the activity of HIV-1 reverse transcriptase. The additional information obtained in the present study includes demonstration of fructose-binding activity and cytokine-inducing activity of Del Monte banana lectin. Fructose binding is an unusual characteristic of plant lectins. It is possible that the banana lectin can be developed into a useful anti-HIV, immunopotentiating and antitumor agent in view of its trypsin stability and thermostability.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
authors.forename: Allen H K
authors.initials: AH
authors.lastname: Cheung
authors.forename: Jack H
authors.initials: JH
authors.lastname: Wong
authors.forename: T B
authors.initials: TB
authors.lastname: Ng
mesh_terms: D001483:Base Sequence; D002853:Chromatography, Liquid; D016207:Cytokines / Q000096:biosynthesis*; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D005632:Fructose / Q000378:metabolism*; D006386:Hemagglutination Tests; D006863:Hydrogen-Ion Concentration; D037102:Lectins / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D028521:Musa / Q000737:chemistry*; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D013696:Temperature
chemical_list: D016207:Cytokines; D017931:DNA Primers; D037102:Lectins; D005632:Fructose