Physico-chemical properties and specific activity of a purified allergen (codfish)

The major allergen (Allergen M) from codfish is an acidic protein, mol. wt. 15000 with 114 amino acid residues and only one sugar (glucose) residue. It is highly active in skin testing on codfish-allergic individuals, in passive transfer (PK) testing and in the radioallergosorbent test (RAST). The activity resists denaturation and incomplete tryptic hydrolysis. Two fragments (TM 1, mol. wt. 8500, and TM 2, mol. wt. 6500) are obtained from allergen M. The fragments are equally active and allergenically identical in biological tests, but somewhat less active than Allergen M itself. Smaller peptides obtained from TM 2 are inactive. The amino acid sequence of TM 2 is given as the first reported example of a full structural analysis of an active allergen. The information obtained in studies of this model allergen is compared with information published from other studies of allergens. Similarities and differences are pointed out.