CATECHOL 1 ,2-DIOXYGENASE FROM ASPERGILLUS NIGER : PURIFICATION AND PROPERTIES.

Abstract

Catcchol 1,2-dioxygenase was partially purified to 60-fold from cell-free extracts of Aspergillus niger grown on anthranilic acid. The purified enzyme was found to be highly unstable. The effects of pH. temperature, metal ions and metal chelating agents on enzyme activity have been studied. The enzyme catalyzes the oxidation of catechol and 4-methyl catechol at the same rate, but does not catalyze the oxidation of 3-methyl ca.techol, 3-isopropyl eatechol and other substrate analogues. The enzyme is completely inhibited by thiol compounds and not affected by thiol inhibitors. The km value for catechol was found to be 5.2 x 103 M.