Hydrolyzes various peptides including beta-endorphin, insulin B chain, dynorphin A, and neurokinin A, with high specificity for the cleavage of the Phe-Xaa bonds. Degradation of gelatin, little activity on hemoglobin. Specificity on B chain of insulin more restricted than that of pepsin A. Does not cleave 1-Phe-|-Val-2, 4-Gln-|-His-5 or 23-Gly-|-Phe-24. Belongs to the peptidase A1 family.