Isolation, purification and assay of the macerating enzyme produced by Penicillium oxalicum Curie and Thom.

Penicillium oxalicum produced two isozymes of polygalacturonase (PG) and a pectate lyase (PL). The enzymes were separated and purified following ammonium sulphate precipitation, ion exchange chromatography, ultrogel column chromatography and isoelectric focusing. The first isozyme of polygalacturonase (PGI) was rather unstable hence its properties could not be much assayed. PGII macerated and killed yam tissue in 4 hours but PL was unable to do so. Enzyme assay for the end-products of degradation of sodium polypectate and yam tissue showed that PGI was an exo-enzyme while PGII and PL were endo-enzymes. Endo-polygalacturonase (PGII) appears to play the major role (as the macerating enzyme) in the pathogenesis of yam tissue infected by P. oxalicum.