Main content area

Biochemical characterization and surfactant properties of horse allergens

Botros, Hany Goubran, Poncet, Pascal, Rabillon, Jacques, Fontaine, Thierry, Laval, Jean‐Marc, David, Bernard
European journal of biochemistry 2001 v.268 no.10 pp. 3126-3136
allergenicity, allergens, galactose, glycosylation, horses, hydrophobicity, mass spectrometry, molecular weight, oligosaccharides, peptides, proteins, rats, sequence homology, surface tension, surfactants
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.