抄録
Endo-polygalacturonase I from Coniothyrium diplodiella has been purified. The purified enzyme was homogeneous on ultracentrifugation and free-boundary electrophoresis. The isoelectric point and the sedimentation coefficient were found to be approximately 7.6 and 2.68S, respectively. The enzyme was completely inactivated by heating at 50°C for 10 min. and at 40°C was most stable in the pH range of 4.0_??_4.5. The enzyme rapidly decreased the viscosity of a solution of pectic acid and released reducing groups by a random attack of glycosidic linkages. Pectin underwent only a slight degradation, which was sufficient to cause a decrease in viscosity but gave little release of reducing groups. The enzyme attacked all of the galacturonides except digalacturonic acid. The extent of hydrolysis of pectin (esterification degree, 64%) and pectic acid was 11.6 and 73.8% respectively.
