59 



attract special attention at first because it was generally thought 

 that the power to decompose hydrogen peroxide was a property 

 common to all ferments (enzymes). However, beginning in 1888 

 with Bergengriin, different investigators discovered that the 

 power to decompose hydrogen peroxide into oxygen and water 

 could exist independently of the ordinary activities of such 

 enzymes as the oxidases, diastase, emulsin, etc. Gottstein stated 

 that the power of cells to break up hydrogen peroxide is due to 

 their nucleic acid content and not to any enzyme, and further- 

 more, this power is shown after the death of the cell as well as 

 during life. In 1901, Loew^'* found, in his studies on the enzymes 

 of the tobacco leaf, that these leaves often caused a very active 

 evoluition of gas from hydrogen peroxide, but yielded none of the 

 tests for oxidases, protein digesting enzymes, and other enzymes. 

 This led him to study the matter more fully, with the result that 

 by precipitation of the leaf extracts with ammonium sulphate and 

 subsequent purification by alcohol precipitation, he obtained 

 preparations that were extremely active in decomposing hydrogen 

 peroxide, but which had no other property agreeing with the 

 other classes of enzymes, such as the starch digesting action of 

 diastase, etc. He named this substance "catalase" and con- 

 sidered that it was a new enzyme. Loew then made a more 

 careful study of catalase and found that it apparently existed 

 in two forms, a-catalase, which is insoluble in water, and the 

 jS-catalase, soluble in water. In a study of its distribution, Loew 

 found that catalase is of practically universal occurrence in both 

 plants and animals, a conclusion fully substantiated by the work 

 of all later investigators. Recent observations made by Apple- 

 man^^ seem to show that catalase may be separated into a water- 

 soluble and -insoluble portion as was previously claimed by Loew, 

 Euler^^ investigated the catalase of the fungus Boletus scaber 

 in a painstaking manner. This catalase proved to be more 

 sensitive to acids than animal preparations, but like them, there 

 seemed to be some connection between the fat content of the 



2^ Loew. Catalase, a New Enzyme of General Occurrence. Report No. 68, 

 U. S. Dept. Agric. 1901. 



2=Appleman. Some Observations on Catalase. Bot. Gazette 50: 182. 1910. 

 ^^Euler. Zur Kenntniss der Katalase. Hofmeister's Beitrage, 7: i. 1908. 



