KTI and BBI protease inhibitor activity in seed storage protein of Iranian soybean cultivars

Kunitz (KTI) and Bowman-Birk (BBI) protease inhibitors are considered the most significant factors that decrease the quality of soybean proteins. In this study, the levels of these proteins were investigated using the ۲D-PAGE, and their activity was evaluated through trypsin and chymotrypsin proteases in ten Iranian soybean cultivars. These results indicated that the Katol cultivar has the lowest concentration of both KTI and BBI proteins and the lowest trypsin and chymotrypsin inhibitory levels.  Therefore, this cultivar is an ideal choice for soybean protein-based diets and could also serve as a valuable parent in breeding programs aimed at improving protein quality in soybean . Moreover, no significant correlation was found between KTI with BBI proteins, nor between these proteins with protease activity. Therefore, it seems that genetic control targeting either KTI or BBI proteins alone may not be an effective approach to improving the quality of soybean proteins. Additionally, no correlation was found between KTI and BBI proteins with agronomic traits. This also suggests that reducing protease inhibitors in soybean proteins does not adversely affect overall soybean performance.

Keywords:

Soybean , Kunitz protein , Bowman-Birk protein , Trypsin inhibitor , Chymotrypsin inhibitor , Agronomic traits