1) Ribonucleic acid (RNA) desaminase in the liver of rats fed 4-dimethylaminoazobenzene (DAB) was studied by means of paper electrophoresis. The activity was expressed by the amount of liberated ammonia and the extent of electromigration of enzyme on the paper was also represented on the activity pattern.
2) Whole homogenate of normal liver, the pathological liver including hepatoma, and the liver of DAB fed rats in their fourth week of experiment showed the similar pattern, in the shape of plateau extending to whole protein zone, although having a slight undulation especially at the peak of the starting line.
3) In the pattern of RNA desaminase in acid and alkaline media, no characteristic difference was observed among the above mentioned hepatic tissues.
4) The pattern of the supernatant covered nearly all the moving part of that of the whole homogenate. The pattern of the sediment coincided with that of the slow moving part of the whole homogenate.