The Purification and Properties of Glutathione Peroxidase of Erythrocytes

Abstract

phenylhydrazine and hydrogen peroxide were prepared fresh as needed for the various experimental procedures. The hydrogen peroxide concentration was determined by titration with a standardized permanganate solution. Horseradish peroxidase was obtained from Nutritional Biochemicals Corporation. Diethylaminoethyl cellulose1 was prepared from Solka-Floe as described by Peterson and Sober (8). Titration curves of the lyophilized preparation showed the presence of 0.9 m.eq. of ionizing groups per gm. of dry material. Methods-All spectrophotometric measurements were made with a model DU Beckman spectrophotometer. Optical density readings at 270 rnp were used as a routine measure of the protein concentration in eluent fractions. The optical density readings at 270 rnp of a solution of the purified enzyme preparation were correlated with the protein nitrogen content of this same sample by a nitrogen analysis carried out by the Kjeldahl procedure (9). Catalase activity was measured by the method of Feinstein (10).