Biochemical characteristics of trypsin inhibitor from wheat grain, beta variety

A homogenous trypsin inhibitor from wheat grain has been characterized. It is a protein of molecular weight 9105 Da and isoelectric point pI = 9.5. It belongs to arginine type inhibitors. The isolated inhibitor does neither inhibit native proteinases from wheat grain nor alpha-chymotrypsin, papein and pepsin. However, it inhibits some proteinases from microorganisms and moulds. It is susceptible to the action of hydrogen peroxide. The inhibitory protein consists of all amino acid residues with the largest amount of glutamic acid, proline and arginine, and the lowest of histidine and tyrosine, respectively.