title: Lectin and alliinase are the predominant proteins in nectar from leek (Allium porrum L.) flowers.
abstract: Analysis of nectar from leek (Allium porrum) flowers by SDS-PAGE revealed the presence of two major polypeptide bands of 50 kDa and 13 kDa, respectively. Using a combination of agglutination tests, enzyme assays and N-terminal sequencing, the polypeptides have been identified as subunits of alliin lyase (alliinase, EC 4.4.1.4) and mannose-binding lectin, respectively. The latter protein is particularly abundant since it represents about 75% of the total nectar protein. Honey produced by bees foraging on flowering leek plants still contains biologically active lectin and alliinase. However, the levels of both proteins are strongly reduced as compared to those in the original nectar. It is evident, therefore, that the lectin as well as the alliinase are inactivated/degraded during the conversion of nectar into honey.
authors.affiliation: Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Heverlee, Belgium. willy.peumans@agr.kuleuven.ac.be
authors.forename: W J
authors.initials: WJ
authors.lastname: Peumans
authors.forename: K
authors.initials: K
authors.lastname: Smeets
authors.forename: K
authors.initials: K
authors.lastname: Van Nerum
authors.forename: F
authors.initials: F
authors.lastname: Van Leuven
authors.forename: E J
authors.initials: EJ
authors.lastname: Van Damme
mesh_terms: D000372:Agglutination Tests; D000490:Allium / Q000737:chemistry* / Q000201:enzymology; D000595:Amino Acid Sequence; D000818:Animals; D001516:Bees; D013437:Carbon-Sulfur Lyases / Q000032:analysis* / Q000737:chemistry; D002352:Carrier Proteins / Q000032:analysis* / Q000737:chemistry; D037222:Collectins; D004591:Electrophoresis, Polyacrylamide Gel; D006722:Honey / Q000706:statistics & numerical data; D037102:Lectins / Q000032:analysis; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000737:chemistry; D037121:Plant Lectins; D017386:Sequence Homology, Amino Acid; D013045:Species Specificity
chemical_list: D002352:Carrier Proteins; D037222:Collectins; D037102:Lectins; D010446:Peptide Fragments; D037121:Plant Lectins; D013437:Carbon-Sulfur Lyases; C019243:alliin lyase