Solubilization of particle-linked urate oxidase by different agents.

Urate oxidase was mostly recovered in a 40 000 g for 20 min subcellular fraction from conventional homogenated. Different agents were able to solubilize the sedimentable enzyme when tested on this crude peroxisomal fraction. The agents increased also total enzyme activity which was recovered in supernatants after centfiguation. If the possible effect of absorption to pellets is to be discounted, the enzyme was practically 100% extracted by six alternated freezing and thawing high alkaline pH, the detergent Hyamine 2389 and high ionic strength of calcium chloride. Triton X-100 was very effective in extracting proteins from the fraction, while it left most of the enzyme activity insoluble. It is suggested that the forces responsible for the integrity of the crystalloid, which was observed by other authors at the electron microscope, and to which the enzyme is believed to be related, are the electrostatic nature.