• Journal of the Korean Society of Food Science and Nutrition
• /
• v.21 no.2
• /
• pp.195-200
• /
• 1992

Rhizopus oryzae CJ-2114 was selected for its strong polygalacturonase activity among various strains of mold found in soil. The optimum pH for the enzyme activity was 4.0 and optimum temperature was 4$0^{\circ}C$. The activation energy for the polygalacturonase was calculated by Arrhenius equation was 2.048㎉/㏖. The reaction of this enzyme followed typical Michaelis-Menten kinetics with the Km value of 54.05mM with the $V_{max}$ of 13.9m mole/min. The enzyme is relatively stable in acidic condition. The activity of polygalactur-onase was inhibited completely by C $u^{2+}$, P $b^{2+}$ and Z $n^{2+}$, $_Mn^{2+}$ at concentration of 1 mM. The enzyme can be inactivated by the treatment with maleic anhydride and iodine. The results indicate the possible involvement of histidine at active site. When polygalacturonase from Rhizopus oryzae CJ-2114 was reacted with poly-galacturonic acid as a substrate mono-, di-, and oligogalacturonic acid were produced at early and mono-, digalacturonic acid produced at late incubation time. time.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.21 no.2
• /
• pp.187-194
• /
• 1992

Rhizopus oryzae CJ-2114 was selected for its strong polygalacturonase activity among various strains of mold found in soil. It was found that the production of polygalacturonase reached to maximum when the wheat bran medium containing 1% albumin, 1% sorbitol and 0.2% (NH$_4$)$_2$C$_2$O$_4$was cultured for 96 hrs at 3$0^{\circ}C$. Polygalacturonase was purified 11.13 fold from Rhizopus oryzae CJ-2114. The purification procedures include ammonium sulfate treatment, gel filtration on Sephadex G-75, G-150 and DEAE-cellulose ion exchange chromatography. Yield of the enzyme purification was 40.3% .Purified enzyme was confirmed as a single band by the polyacrylamide gel electrophoresis. When the purified enzyme was applied to SDS-poly-acrylamide gel electrophoresis, the molecular weight was estimated to be 47,000. The amino acid composition indicated relatively high contents of glutamic acid and glyrine.