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Biochemical characterization and surfactant properties of horse allergens

Author:
Botros, Hany Goubran, Poncet, Pascal, Rabillon, Jacques, Fontaine, Thierry, Laval, Jean‐Marc, David, Bernard
Source:
European journal of biochemistry 2001 v.268 no.10 pp. 3126-3136
ISSN:
0014-2956
Subject:
allergenicity, allergens, galactose, glycosylation, horses, hydrophobicity, mass spectrometry, molecular weight, oligosaccharides, peptides, proteins, rats, sequence homology, surface tension, surfactants
Abstract:
A new allergen from horse dander, Equ c 5 has been purified. Its biochemical and biophysical properties have been characterized and compared with those of Equ c 1, Equ c 2 and Equ c 4. Their molecular masses, determined by mass spectrometry, were 22 kDa for Equ c 1, 16 kDa for Equ c 2, 18.7 kDa for Equ c 4 and 16.7 kDa for Equ c 5. Their pI values were between 3.8 and 5.25. Equ c 2 and Equ c 5 are not glycosylated, while Equ c 4 contains a tri‐antennary tri‐sialylated N‐linked glycan. Linkages of terminal N‐acetylneuraminic acid to galactose were: α‐(2→6) in Equ c 4, and both α‐(2→3) and α‐(2→6) in Equ c 1. Oligosaccharide portions of Equ c 1 or Equ c 4 were barely involved in IgE‐immunoreactivity. Partial N‐terminal sequence of Equ c 4 shares a significant sequence homology with the rat submandibular gland protein A. No matching was found for two internal peptides of Equ c 5. Surfactant properties of horse allergens as well as other proteins were investigated. In contrast to Equ c 2 and Equ c 3, solutions of Equ c 1, Equ c 4 and Equ c 5 significantly lowered the surface tension. Relationship between a property such as this, involving oriented hydrophobic patches of a molecule and allergenicity, is addressed.
Agid:
96279