PARTIAL PURIFICATION AND SOME PROPERTIES OF A POLYGALACTURONASE PRODUCED EXTRACELLULARLY BY Alternaria alternata (FR.) KEISSL.

Abstract

A polygalacturonase  was purified  to about 480 fold from the culture filtrate of  Alternaria alternata  (Fr.) Keissl. The partially purified enzyme had a pH optimum of 5.2 and activation energy of 4.77K  cal/mole for polygalacturonic acid (sodium salt). Vmax, and Km were found to be 333u moles of  galacturoric acid liberated per bout at 37 °  and 0.106% (2.9  X 10^-5 M)  polygalacturonic acid respectively. The enzyme was only slightly activated by Ca^+ 2  and Co^+2 . Tannic acid inhibited the activity  but chlorogenic, caffeic and ferulic acids did not have any effect. The purified enzyme did not  utilize low chain length oligogalacturonides indicating that it might be an endopolygalacturonase.