Crystalline beef liver catalase: A simplified method of preparation

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nearly always resulted in complete suppression of aerobic phosphorylation, and usually even 5 x 10-e to 10-b gave complete suppression or significantly lowered esterification rates (Table II). Still lower concentrations of thyroxin sometimes resulted in an increased phosphorylation value, possibly indicating, that thyroxin in small concentrations may be required for this fundamental reaction. The uncoupling effect of thyroxin on oxidative phosphorylation can readily explain the effect of this compound on the basal metabolism rate; its other known effects seem to be secondary responses to this change. REFERENCES 1. LEHIVINGER, A. L., J. Riol.

Chem. 178, 625 (1949). CARL i-&RTIUS BENNO HESS

Physiol.-them. Znstifut, Ttibingen, Germany, Received August B’, 1951

Salivary Peroxidase As far as we are aware peroxidase has not been previously reported t,o occur in saliva. Nevertheless, we have observed that a strong test for this enzyme is given by the saliva of man, horse, cow, sheep, dog, and cat. The reagents employed were hydrogen peroxide with guaiacol, pcresol, or pyrogallol. A portion of the peroxidase of human saliva is in solution, while another portion is present in the sediment. We have concentrated salivary peroxidase some tenfold by ammonium sulfate and alcohol fractionation. It may be claimed by some that the peroxidase test given by saliva is really due to the presence of hemoglobin. However, to give even a weak peroxidase test, solutions must contain a visible amount of hemoglobin; our specimens of saliva, which give a strong test, are colorless. ACKNOWLEDQMENT

We wish to thank the Rockefeller Foundation for financial support. WALTER MOSIMANN’ JAMES B. SUMNER

Laboratory of Enzyme Chemistry, Cornell University, Ithaca, New York Received August 23, 1951

Crystalline Beef Liver Catalase: A Simplified Method of Preparation There have been several modifications of the original (1) method for preparing crystalline beef liver catalase. The procedure described below has the advantage that the use of dioxane, ammonium sulfate, and dialysis is avoided. The method, however, is suitable only for beef liver catalase. METHOD

Put fresh beef liver through a meat grinder four times. Extract the catalase at room temperature by the occasional shaking of each kilogram of ground liver for 10 min. 1 “Stiftung fur Stipendien auf dem Gebiete der Chemie” (Switzerland).

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with 1 1. of distilled water. To each liter of material add 480 ml. of chilled solution of chloroform, I part; and ethyl alcohol, 2 parts. Shake violently for about 30 sec. and at once filter in the ice chest through Whatman No. 12 filter papers. The next day the filtrates will contain a sediment of catalase crystals. This sediment is centrifuged down in a refrigerated centrifuge and the supernatant liquid is discarded. The crystals are dissolved at room temperature in distilled water (30-40 ml. for each kilogram of liver used). The solution is centrifuged to remove a white amorphous impurity, decanted, and chilled in the ice chest for 12-24 hr. Catalase will precipitate as needles. ACKNOWLEDQMENTS

I wish to thank the Rockefeller Foundation for financial support and Professor James B. Sumner for encouragement. REFERENCES 1. SUMNER, J. B., AND DOUNCE, A. L., J. Biol. Chem. 121, 417 (1937). Laboratory of Enzyme Chemistry Cornell University, Ithaca, New York Received Auclust IS. 1951

WALTER MOSIMANN~

1 “Stiftung fur Stipendien auf dem Gebiete der Chemie” (Switzerland).