Polygalacturonase (PG) from solid culture extract of Rhizopus japonicus IF0 5318 was purified by DEAE Sephadex A-50, CM Sephadex C-50 and Sephadex G-100 column chromatography. Finally the PG was purified approximately 121 folds based on its activity. The optimum pH and temperature on the PG activity were at pH 4.5 and 45℃ respectively and this enzyme was most stable at pH 7.5 and up to 35℃. The purified PG gives a molecular weight of 44,000 Da and Km value of 5.21 mg/ml. Furthermore, the results of the effect of some metal ions and inhibitors on enzyme activity showed that Zn^<2+>, Mg^<2+>, Cu^<2+>,Ca^<2+>, Mn^<2+> and Al^<3+> enhanced fairly the PG activity (1-9%) but K^+, Fe^<2+>, Ni^<2+>, Ba^<2+>, and Na^<2+> inhibited slightly the PG activity (1-6%) while Li^+ and urea inhibited about 20% of PG activity.
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