Purification and partial characterization of a thiol proteinase inhibitor from Enterolobium contortisiliquum beans.

A thiol proteinase inhibitor was purified from Enterolobium contortisiliquum beans by affinity chromatography on carboxy-methylated-papain-Sepharose. The inhibitor represents a single polypeptide chain with a molecular mass of 60 kDa and inactivates papain (Ki = 0.58 x 10(-9) M) and bromelain. The inhibitor shows activity in the pH range 2 to 10 and at temperatures up to 60 degrees C.