Preferential cleavage: hydrophobic and aromatic residues in P1 and P1′ postitions. Cleaves Phe-Val, Gln-His, Glu-Ala, Ala-Leu, Leu-Tyr, Tyr-Leu, Gly-Phe, Phe-Phe and Phe-Tyr bonds in the β chain of insulin
One unit corresponds to the amount of enzyme which increases the absorbance at 280 nm by 0.001 per minute at pH 2.0 and 37 °C (Hemoglobin, Catalog No. 51290, as substrate); 15,000 absorbance units as described above are equivalent to ∼1 Bergmeyer unit. One Bergmeyer unit is the amount of enzyme which hydrolyzes 1 μmole Acetyl-L-phenyl-3,5-diiodo-L-tyrosine at pH 2.0 and 37 °C.
Optimum pH is 2-4. Active in 4 M urea and 3 M guanidine HCl. Stable at 60 °C. Pepsin is irreversibly inactivated at pH 8.0 - 8.5.