Resistance of purified seed storage proteins from sesame (Sesamum indicum L.) to proteolytic digestive enzymes

Sesame has been increasingly associated with food allergy. The main seed storage proteins of sesame (the 2S albumin and the 7S and 11S globulins) were purified and subjected to proteolysis with pepsin, trypsin and chymotrypsin. The degree of proteolysis obtained was monitored by SDS–PAGE, followed by densitometry of the main bands. The 2S albumin was found to be stable to proteolysis, being extremely resistant to pepsin, and relatively resistant to trypsin and chymotrypsin. The 7S and 11S proteins were relatively labile to pepsin. Acidic polypeptides from the 11S protein were more susceptible to proteolysis than the basic polypeptides. Both 7S and 11S proteins generated what appeared to be stable polypeptides after proteolysis with trypsin and chymotrypsin. The results are discussed in relation to similar studies on related seed storage proteins, available structural information, and the potential allergenicity of the sesame proteins.