ABSTRACT
Previous studies from our laboratory have demonstrated that the fungus Penicillium frequentans produces high levels of polygalacturonase and pectinesterase. Endopolygalacturonase I (Endo-PG I) and Exopolygalacturonase I (Exo-PG I) were previously purified and characterized. In the present study two extracellular polygalacturonases were separated, partially purified and biochemically characterized. Both were characterized as exopolygalacturonases so they were named exopolygalacturonase II (Exo-PG II) and exopolygalacturonase III (Exo-PG III) which had a molecular mass of 63 kDA (Exo-PG II) and 79 kDA (Exo- PG III). The K(m) values were 1.6 and 0.059 g/L and the V(max) values were 2571 and 185 U/mg, respectively. The optimim temperature was 50ºC for both enzymes, while the optimum pH was 5.0 for Exo-PG II and 5.8 for Exo-PG III.