THE USE OF DIFFERENT PROTEASES TO HYDROLYZE GLIADINS

Abstract

Gliadins represent alcohol-soluble fraction of wheat storage proteins which is responsible for development of celiac disease. The only and effective treatment for celiac disease is strict adherence to a gluten-free diet excluding any food made with wheat, as well as rye, barley and possibly oat flour. Enzymatic modification of wheat gliadins seems to be an alternative method for decreasing of celiac activity. The aim of our study was a trial of enzymatic modification of wheat gliadins using fungal (Aspergillus sp., Aspergillus oryzae, Aspergillus niger) and bacterial (Bacillus licheniformis, Bacillus stearothermophilus, Bacillus thermoproteolyticus, Streptomyces griseus) proteases. The reaction was performed up to 60 min, stopped by addition of appropriate synthetic inhibitor and products of limited proteolysis were analyzed by SDS-PAGE method. From fungal proteases most effective proteolytic activity was observed using acid proteinase from A. niger since wheat gliadins and low molecular weight peptides were completely degraded. Bacterial proteases form B. licheniformis and B. thermoproteolyticus acted very effective and as the result of hydrolysis, the products of lower molecular weight (<15 kDa) occurred. Most of the wheat gliadins were susceptible to proteolysis by examined bacterial enzymes (exception were protease from B. stearothermophilus and S. griseus). Although wheat gliadins are susceptible to enzymatic degradation, further analysis (e.g. immunochemical or mass spectrometry) are desirable to confirm if the products of proteolysis have lost or at least partially decrease their celiac activity.