pH profile (a) and pH stability (b) of the alkalinecrude protease from viscera of the red scorpionfish.Protease activity was assayed in the pH range from 5.0 to12.0 at 50◦C. The maximum activity obtained at pH 10.0was considered as 100% activity. The pH stability wasdetermined by incubating the enzyme in different buffersfor 1 h and 24 h at 4◦C, and the residual enzyme activitywas determined at pH 10.0 and 55◦C using casein as asubstrate. The activity of the enzyme before incubation wastaken as 100%. Buffer solutions used for pH activity andstability are presented in “Materials and Methods”.