STUDIES ON THE ENZYME PRODUCED BY YEASTS .6. PURIFICATION, CRYSTALLIZATION AND SOME PROPERTIES OF ENDOPOLYGALACTURONASE FROM KLUYVEROMYCES-FRAGILIS

The production of pectolytic enzyme [used as a processing aid in vegetable and fruit juice production] in the genus Kluyveromyces was investigated. The production of the enzyme was dependent on the strain, and some strains belonging to K. fragilis, K. marxianus and K. wickerhamii produced this enzyme among 11 species [K. africanus, K. drosophilarum, K. lactis, K. phaffi, k. polysporus, K. thermotolerans, K. vanudenii, K. waltii] (29 strains) of the genus Kluyveromyces. K. fragilis IFO 0288 produced at least 4 endo-polygalacturonases which have different MW. The dominant endo-polygalacturonase in the culture filtrate of the strain was purified and isolated as crystals. The purified enzyme was homogeneous based on analysis by polyacrylamide gel electrophoresis and ultracentrifugation. The enzyme was a glycoprotein having an isoelectric point around pH 5.6. The sedimentation coefficient (s20,w) was 3.77S, and the MW was around 33,000. The enzyme contained aspartic acid (asparagine), serine, threonine and glycine at relatively high levels. The enzyme showed the highest activity around pH 5.0 and was stable at pH 5.0 up to 30.degree. C. With the enzyme, and activity which releases highly polymerized pectin from various protopectins (protopectinase activity) was found.