title: Identification of tropomyosin and arginine kinase as major allergens of Portunus pelagicus (blue swimming crab).
abstract: Crab is an important source of food allergen. Tropomyosin represents the main   crab allergen and is responsible for IgE cross-reactivity between various species of crustaceans.   Recently, other new crab allergens including arginine kinase have been identified. However,   information on allergens of the local Portunidcrab is not available. Thus, the aim of this study   was to identify the major allergens of Portunus pelagicus (blue swimming crab) using the   allergenomics approach. Raw and cooked extracts of the crab were prepared from the crab   meat. Protein profile and IgE binding pattern were demonstrated by sodium dodecyl sulfate-polyacrylamide   gel electrophoresis (SDS-PAGE) and immunoblotting using sera from 30 patients   with crab allergy. The major allergens of the crab were then identified by two-dimensional   electrophoresis (2-DE), followed by mass spectrometry analysis of the peptide digests. The   SDS-PAGE of raw extract revealed approximately 20 protein fractions over a wide molecular   weight range, while cooked extract demonstrated fewer protein bands. The raw extract also   demonstrated a higher number of IgE reactive bands than the cooked extract. A heat-resistant   protein of 36 kDa has been identified as the major allergen in both raw and cooked extracts.   In addition, a heat-sensitive protein of 41 kDa was also recognized as a major allergen in raw   crab. The 2-DE gel profile of the raw extract demonstrated about >100 distinct proteins spots   and immunoblotting of the 2-DE profile demonstrated at least 12 different major IgE reactive   spots with molecular masses between 13 to 250 kDa and isoelectric point (pI) values ranging   from 4.0 to 7.0. The 36 and 41 kDa proteins were identified as the crab tropomyosin and   arginine kinase, respectively by mass spectrometry. Therefore, this study confirmed that   tropomyosin and arginine kinase are the major allergens of the local Portunid crab, P. pelagicus.
authors.affiliation: Department of Biology, Faculty of Science and Mathematics, Sultan Idris Education University, 35900 Tanjong Malim, Perak, Malaysia. rosmilah@fsmt.upsi.edu.my
authors.forename: M
authors.initials: M
authors.lastname: Rosmilah
authors.forename: M
authors.initials: M
authors.lastname: Shahnaz
authors.forename: H M Y
authors.initials: HM
authors.lastname: Zailatul
authors.forename: A
authors.initials: A
authors.lastname: Noormalin
authors.forename: I
authors.initials: I
authors.lastname: Normilah
mesh_terms: D000485:Allergens / Q000032:analysis / Q000276:immunology*; D000818:Animals; D001122:Arginine Kinase / Q000032:analysis / Q000276:immunology*; D003386:Brachyura / Q000276:immunology / Q000378:metabolism*; D003429:Cross Reactions / Q000276:immunology; D015180:Electrophoresis, Gel, Two-Dimensional; D005512:Food Hypersensitivity / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D013058:Mass Spectrometry; D008970:Molecular Weight; D012758:Shellfish / Q000009:adverse effects*; D014335:Tropomyosin / Q000032:analysis / Q000276:immunology*
chemical_list: D000485:Allergens; D014335:Tropomyosin; D007073:Immunoglobulin E; D001122:Arginine Kinase