Cysteine protease responsible for the cleavage of kiwellin into kissper and KiTH. Specificity close to that of papain. Fruit, present in small cells of the outer pericarp of mature fruit, but not large cells. Expressed in ripening fruit, levels are highest at the harvest of fruit and decrease as the fruit ripens. Causes an allergic reaction in human. Binds IgE. Belongs to the peptidase C1 family.