ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 24, Number 1
JKCSEZ 24(1)
February 20, 1980 

Pyrocatechase as a phenolytic dioxygenase was extracted from the benzoate-induced cells of a soil bacterium, a member of Pseudomonadaceae, and purified partially by DEAE-cellulose ion-exchange chromatography and Sephadex G-75 gel filtration. Final preparation of the enzyme yielding 200 fold purification over the crude extracts showed a specific activity of about 40 μmoles per minute per mg protein based on catechol as the substrate. The enzyme showed a very limited substrate specificity towards catechol for its catalytic activity. Based on the inhibition study with the substrate analogues, it was assumed that ortho dihydroxy groups on the aromatic ring may participate in the enzyme-substrate binding. The Km value for catechol was obtained as 1.9 × 10-6 M, and the optimum activity of the enzyme was obtained at the pH range of 7∼10 and 35℃. With SH-group blocking agents the enzyme was inhibited seriously.The activity of enzyme was also inhibited by the addition of some heavy metals, Ag+ and Cu2+, but was not affected by EDTA. General property of the enzyme was characterized and the possible nature of the enzyme active center was also discussed.