64 ENZYMES 



catalase, which was thought to be a nucleoprotein,'^ and ^-catalase, 

 which has the properties of an albumose. It has been demonstrated 

 by Bach and Chodat that peroxides are contained in plant cells, and 

 they also occur in animal cells. According to Golodetz and Unna^ 

 the catalases are held in the cytoplasm of the cells while the peroxida- 

 ses are in the nucleus. Just what function the catalase performs is at 

 present merely a matter of speculation, but that it serves an important 

 purpose is indicated by the observation of Burge* that the amount of 

 catalase in tissues varies directly with their activity. He also as- 

 cribes the specific dynamic action of proteins to their causing an 

 increase in blood catalase. Becht,^ however, questions the validity 

 of the evidence so far brought forward in support of the hypothesis 

 that catalase is essentilly responsible for tissue oxidation.^ 



Loew considers that it destroys peroxides formed in metabolism, 

 which|are]very poisonous to cell life. Shaffer has found evidence that 

 under the influence of catalase the oxygen liberated is in the molecular 

 form, O2, and therefore relatively inert; whereas when peroxides 

 spontaneously decompose, they liberate atomic oxygen which is an 

 active oxidizing agent. He found that uric acid is oxidized by per- 

 oxide of hydrogen, but when catalase is present, this oxidation is 

 prevented. According to this the function of catalase is rather to 

 prevent dangerous forms of oxidation than to help in normal oxi- 

 dative proceses. For the present, however, nothing can be said 

 positively on this subject. 



Occurrence of Catalase under Normal and Pathological Conditions.'' — Battelli and 

 Stern found that the catalytic power of the tissues endures many hours after 

 death. Its abundance is different for different organs of the same animal, but 

 remarkably constant for the same organ in the same species. In general the order 

 in'^decreasing strength is: liver, kidney, blood, spleen, gastro-intestinal mucosa, 

 salivary glands, lung, pancreas, testicle, heart, muscle, brain; but this order varies 

 in different species. Catalase is abundant even in the early embryo (^lendel and 

 Leavenworth) and in sea urchin eggs it increases rapidly after they are fertilized 

 (Lyon). 8 Leucocytes contain little, most of that in the blood being in the stroma 

 of the red blood-corpuscles. The body fluids contain little or none. Injected 

 intravenously, catalase (of the liver) is destroyed rapidly, and docs not appear in 

 the'-urine; it does not cause any toxic effects, nor does it increase resistance to 

 poisoning by venoms. The tissues also contain anti-catalases, and still further a 

 substance which protects the catalase froni the anti-catalase; this protective sub- 

 stance is called the pliilocatalase by Battelli and Stern. 



The gas evolved by the action of pus on H2O2 was found by Marshall' to be pure 

 oxygen, each c.c. of a certain sample of pus examined liberating 133.9 c.c. of gas. 

 The active constituent of pus, he states, is contained in the serum and not in the 



2 Not corroborated by Waentig and Gierisch, Fermentforsch., 1914 (1;, 165. 



' Berl. klin. Woch., 1912 (49), 1134. 



•' vVmer. Jour. I'liysiol., 191G (41), 153; 1917 (42), 373; 1919 (48). 133. See also 

 Alvarez and Starkweather, ibid.; 1918 (47), GO; Dutcher, Jour. Biol. Chem., 1918 

 (36), 63. 



5 Amer. Jour. Physiol., 1919 (48), 171. 



8 See also Stelilc, Jour. Biol. Chem., 1919 (39), 403. 



^ Concerning the catalase of lower animals see Ziegcr, Biochem. Zeit., 1915 

 (69), 39. 



8 Amer. Jour. Physiol., 1909 (25), 199. 



» Univ. of Pcnn. Med. Bull., 1902 (15), 366. 



