SOME OBSERVATIONS ON CATALASE 
CONTRIBUTIONS FROM THE HULL BOTANICAL LABORATORY 139 
CuHas. O. APPLEMAN 
(WITH ONE FIGURE) 
During the course of an investigation now in progress on the 
physiological behavior of enzymes in after-ripening of the potato 
tuber, it became necessary to investigate fully the best method for 
the quantitative determination of catalase in this organ. Some of 
the results thus obtained may be of general interest. 
DISTRIBUTION AND FUNCTION OF CATALASE 
SCHOENBEIN (1863) was the first to observe the power of various 
vegetable and animal extracts to decompose hydrogen peroxid 
with evolution of oxygen. He concluded that the enzymes occur- 
ring in the organisms were responsible for this phenomenon. This 
power of hydrogen peroxid decomposition was considered a more 
or less general property of enzymes until Lorw (1) showed that 
this property of tissues is due to a special enzyme to which he gave 
the name catalase. Its claim for a place in the category of enzymes — 
at this time seems to be based wholly upon its sensitiveness toward 
heat, acids, and various poisons. ; 
Catalase is probably the most widely distributed of any of the 
known enzymes. In fact, its occurrence is so general that LOEW 
concluded that there did not exist a group of organisms, OF any 
organ, or even a single vegetable or animal cell, that did not co¥ 
tain some catalase. An enzyme of such general occurrence might 
naturally be supposed to possess an important function in the 
economy-of nature. This may yet prove to be the case, but at 
present its position in this respect is uncertain. Little 1s ae 
known regarding its mode of action on hydrogen peroxid. Definite 
knowledge on this point is limited to the fact that molecular instead 
of atomic oxygen results from the decomposition, and in this respect 
it differs from the other hydrogen peroxid catalysts. 3 
Botanical Gazette, vol. 50] i 
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