Enzymatic activities of Alternaria alternata allergenic extracts and its major allergen (Alt a 1).

Several allergens from Alternaria alternata have been isolated allowing some of them to be identified and characterised. Despite the fact that the major allergen of A. alternata (Alt a 1) has been extensively produced by recombinant technology, its biological activity still remains unknown. In the present study, extracts from culture filtrates were used to evaluate the intra-specific variability of the enzymes and also as a source for isolating and purifying native Alt a 1. This was purified by affinity chromatography using antibody anti-recombinant Alt a 1 (produced in Escherichia coli). Enzyme activities were analysed by the API-ZYM System screening method. Results demonstrated the high variability of enzyme activities among the different strains. Only activities corresponding to phosphatases, esterases and beta-glucosidase were expressed by 100% of the strains. Both native and recombinant Alt a 1 showed phosphatase and esterase activities, suggesting that the glucidic moiety of this allergen does not significantly affect its enzyme activity.