CATALA8E 60 



is shown by those disorders, such as alkaptonuria and diabetes, in which 

 tlio body loses the power to oxidize a certain cliemical substance while 

 retaining' the normal power to oxidize innumerable other substances. 

 Aecordinof to Lillie ' '" the oxidative processes in cells take place most 

 actively in relation to the membrane surfaces (or phase boundaries) of 

 the cells. Of the oxidizing enzymes as yet identified none can be con- 

 sidered as of importance in the energy-producing oxidations of the 

 body (iiattelli and Stern), all the enzymes of this class yet known be- 

 ing apparently concerned with less essential oxidizing processes; it is 

 indeed possible that the essential oxidation of food-stutt's may not be 

 dependent on enzymes (Engler and Herzog).'^-'' An agent accelerating 

 the essential oxidizing activities of the tissues has been described by 

 Battelli and Stern '"^ under the name of pneUi, and an antipneuniin 

 which holds it in check. Closely related to the oxidizing enzymes is — 

 Catalase. — It has long been known that most enzymes possess the 

 power of decomposing hydrogen peroxide, with liberation of oxygen ; 

 but it was not until 1901 that it was finally demonstrated by Loew 

 that this property was due to a separate enzyme and was independent 

 of the specific properties of the various other enzymes. This ferment 

 is very wide-spread, and so is generally obtained along with the other 

 enzymes when attempts are made to isolate them from the cell. It 

 was named catalase by Loew, and he described two fonus, a-catalase, 

 which seems to be a nucleoprotein,"'*'' and (i-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 peroxidases 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 amoimt of catalase 

 in muscles varies directly with their activity. 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 cata- 

 lase the oxygen liberated is in the molecular form, O^, 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 peroxide 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 oxida- 

 tion than to help in normal oxidative processes. P^'or the present, 

 however, nothing can be said positively on this subject. 



T4a Jour. Biol. Chem., 1913 (15), 2.37. 



75Zeit. physiol. Chem., 1009 (59), 327. 



76Biocliem. Zeit., 1911 (33), 315; 1911 (36), 114. 



76a Xot corroborated tjv Waentifj and Gierisch, Fermentforsch., 1914 (1). 165. 



77Berl. klin. Woch., 1912 (49), 11,34. 



"aAmer. Jour. Pliysiol., 1910 (41), 153; 1917 (42), 373. 



