Variants of Trypsin Inhibitors in Cultivated and Wild Barley and Analysis of Their Antitrypsin Activity

Abstract

Five variants of trypsin inhibitors were found in 80 cultivated and 20 wild spring barley accessions studied by native alkaline electrophoresis with subsequent development of antitrypsin activity. Three of the variants corresponded to the previously described BTI-CMe1, CMe2, and CMe3 proteins. The other two were new and were designated as BTI-CMe4 and BTI-CMe5. CMe4 occurred in both cultivated and wild barley, CMe5 was found only in wild barley. Out of 12 cultivars studied, cultivars with CMe4 variant were characterised by the lowest activity. Besides the main trypsin inhibitor, an additional zone of antitrypsin activity was found in each BTI-CMe variant of cultivated barley. It was shown that BTI content varied significantly among varieties. These differences were associated with BTI variants and did not correlate with the level of soluble protein in grain.