Purification and Characterization of an Endopolygalacturonase Produced by Sclerotinia Sclerotiorum

An endopolygalacturonase (endo-PG), was purified from the culture medium of a local isolate of Sclerotinia sclerotiorum with ammonium sulphate precipitation, cation exchange chromatography and gel filtration. The purified endo-PG had a molecular mass of approximately 18 kDa estimated by gel filtration. The isoelectric point was determined by isoelectric focusing to be approximately 8, suggesting that PG II possesses a net positive charge at physiological pHs. The pH optimum for the enzyme was at pH 4.5. The endo-PG showed essentially the same affinity for pectin and polygalacturonic acid as substrates.