Isolation and characterization of proteolytic enzymes from the latex of Synadenium grantii Hook, 'f'

Two fractions showing proteolytic enzymes have been obtained from the latex of Synadenium grantii Hook, 'f', using gel-filtration and anion-exchange chromatographic techniques. Both these proteases have the same molecular mass of 76+/-2 kDa each. They exhibit maximal activity at pH 7.0 and at a temperature of 60 degreesC. They display stability over a pH range from 5-10 and are also highly thermostable. Irreversible inhibition by PMSF indicates that they are serine proteases. In addition, histidine residues also appear to play an important role in catalysis as evidenced by inhibition with DEPC. They also exhibit similarity with respect to pH and temperature optima, kinetic properties and thermal stability. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.