doi.wiley.com
Keli Ou 1 *, Teck K. Seow 1, Rosa C. M. Y. Liang 1, Bee W. Lee 2, Denise L. M. Goh 2, Kaw Y. Chua 2, Maxey C. M. Chung 1 3
1Bioprocessing Technology Center,
2Department of Pediatrics, Faculty of Medicine,
3Department of Biochemistry, Faculty of Medicine, Singapore National University of Singapore, Singapore
email: Keli Ou (btcoukl@nus.edu.sg)
*Correspondence to Keli Ou, Bioprocessing Technology Centre, National University of Singapore, 10 Medical Drive, Singapore 117597 Fax: +65-796-9596
Keywords
Bird’s Nest • Allergen • Immunoreaction • Two-dimensional gel electrophoresis • Edman degradation • Mass spectrometry
Abstract
For centuries, the edible nests of Collocalia spp. (Bird’s Nests) have been used as a Chinese delicacy that had been claimed to be an effective health-giving tonic. However, clinical
studies indicated that in Singapore, Bird’s Nest is the most common cause of food-induced anaphylaxis in children, which could lead to potentially life-threatening allergenic reactions. The purpose of this study was to characterize the major allergens in Bird’s Nest by using the combined technologies of two-dimensional gel electrophoresis (2-DE), immunochemistry, N-terminal protein sequencing, and mass spectrometry. Results from the immunostaining of the Western blots of the Bird’s Nest 2-DE separated proteins with the sera from allergic patients indicated the presence of a major allergen of 66 kDa. Initial searches of the matrix assisted laser desorption/ionization – time of flight – mass spectrometry (MALDI-TOF-MS) tryptic peptide masses of the allergen in the SWISS-PROT and NCBI nonredundant databases revealed that this protein was novel. Based on the partial protein sequence information obtained from N-terminal microsequencing and nanoelectrospray-tandem MS, the 66 kDa immunoreactive allergen was found to be homologous to ovoinhibitor, a Kazal-type serine protease inhibitor, which is one of the dominant allergens found in chicken egg white.
