PURIFICATION AND SOME PROPERTIES OF ENDOPOLYGALACTURONASE FROM RHIZOPUS SP LKN

An endopolygalacturonase of Rhizopus sp. strain LKN, one of several isolates from tempe starter (ragi), was purified 235-fold by CM-Sephadex C-50, DEAE-Sephadex A-50 ion exchange chromatographies and Sephadex G-75 gel filtration. The purified enzyme was homogeneous by SDS-PAGE with a M(r) of 38.5 kDa. Its K(m) value for pectic acid was 2 mg/ml. It was stable at pH 4.5 to 11 and up to 50-degrees-C, with optimum activity at pH 4.5 to 4.75 and 55 to 60-degrees-C. Some ionic compounds enhanced the enzyme activity, whereas tannic acid at 0.5 mM caused about 90% inhibition.