title: Passiflin, a novel dimeric antifungal protein from seeds of the passion fruit.
abstract: The intent was to isolate an antifungal protein from seeds of the passion fruit (Passiflora edulis) and to compare its characteristics with other antifungal proteins and bovine beta-lactoglobulin in view of its N-terminal amino acid sequence similarity to beta-lactoglobulin. The isolation procedure entailed ion-exchange chromatography on Q-Sepharose, hydrophobic interaction chromatography on Phenyl-Sepharose, ion-exchange chromatography on DEAE-cellulose, and FPLC-gel filtration on Superdex 75. The isolated 67-kDa protein, designated as passiflin, exhibited an N-terminal amino acid sequence closely resembling that of bovine beta-lactoglobulin. It is the first antifungal protein found to have a beta-lactoglobulin-like N-terminal sequence. Its dimeric nature is rarely found in antifungal proteins. It impeded mycelial growth in Rhizotonia solani with an IC(50) of 16 microM and potently inhibited proliferation of MCF-7 breast cancer cells with an IC(50) of 15 microM. There was no cross-reactivity of passiflin with anti-beta-lactoglobulin antiserum. Intact beta-lactoglobulin lacks antifungal and antiproliferative activities and is much smaller in molecular size than passiflin. However, it has been reported that hydrolyzed beta-lactoglobulin shows antifungal activity. The data suggest that passiflin is distinct from beta-lactoglobulin.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China. lamszekwan@yahoo.com.hk
authors.forename: S K
authors.initials: SK
authors.lastname: Lam
authors.forename: T B
authors.initials: TB
authors.lastname: Ng
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000935:Antifungal Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy; D002417:Cattle; D045744:Cell Line, Tumor; D005658:Fungi / Q000187:drug effects*; D006801:Humans; D007782:Lactoglobulins / Q000494:pharmacology*; D008969:Molecular Sequence Data; D029598:Passiflora; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry* / Q000494:pharmacology / Q000627:therapeutic use; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use; D012639:Seeds
chemical_list: D000935:Antifungal Agents; D007782:Lactoglobulins; D010936:Plant Extracts; D010940:Plant Proteins; C539927:passiflin protein, Passiflora edulis