OBSOLETE. Catalysis of the hydrolysis of peptide bonds. Preferential cleavage: hydrophobic, preferably aromatic, residues in P1 and P1' positions. Cleaves Phe1-Val2, Gln4-His5, Glu13-Ala14, Ala14-Leu15, Leu15-Tyr16, Tyr16-Leu17, Gly23-Phe24, Phe24-Phe25 and Phe25-Tyr26 bonds in the B chain of insulin.