Purification and Properties of Pyrazon Dioxygenase from Pyrazon‐Degrading Bacteria

Abstract

Chromatography on DEAE-cellulose and gel filtration on Sephadex revealed that pyrazon dioxygenase from pyrazon-degrading bacteria consists of 3 different enzyme components. No component alone oxidizes the phenyl moiety of pyrazon; only when the 3 components are combined can oxidation be detected. EPR and UV measurements showed the protein nature of the 3 components. Component A1 (MW .apprx. 180,000, red-brown in color) is an Fe protein containing 2 mol of Fe and 2 mol of inorganic S/mol of protein. This enzyme component was purified to homogeneity in disc electrophoresis. Component A2 is a yellow protein of a MW of .apprx. 67,000. FAD was the prosthetic group of this protein. Component B (MW .apprx. 12,000, brown in color) is a protein of the ferredoxin type, which was purified to homogeneity, as demonstrated by disc electrophoresis. A hypothetical scheme for the cooperation of the components is proposed. Component A2 accepts as cosubstrate NADH and functions as a ferredoxin reductase. The ferredoxin component B function 3 as an electron carrier. The conversion of the substrates is effected by component A1, the terminal dioxygenase.