THE INFLUENCE OF LOW TEMPERATURES UPON 



ENZYMES 



A review 



JOSEPH SAMUEL HEPBURN 

 (University Fellow in Biological Chemistry, Columbia University, 1912-1913) 



Introduction. The influence of low temperatures on enzymes 

 is a subject of growing importance to the chemist, the biologist, and 

 the bromatologist. Problems in this field may be studied from 

 either the potential or the kinetic side; for either the resistance of 

 an enzyme to, or its activity at, low temp. may be investigated. 

 Various researches, conducted during the last half Century, have 

 demonstrated that enzymes survive exposure to low temp. and also 

 act as catalysts at such temp. The reports of these researches are 

 widely scattered in the literature ; and f requently the original papers 

 may be obtained for consultation only with difficulty. It is the pur- 

 pose of this paper, which is based on primary sources, to give a re- 

 sume of our present knowledge of this subject. One section is de- 

 voted to the resistance of enzymes to low temp., and one to their 

 activity at such temp. In the first section, the following data for 

 each enzyme 'are given, so far as they have been recorded in the 

 original literature: source of enzyme; temp., time and mode of ex- 

 posure. In the second section, the data given for each enzyme, so 

 far as recorded by the various observers, are: source of enzyme, 

 temp. and time of incubation, substratum, degree of progress of re- 

 action, and results of comparative experiments carried out at higher 



temp. 



2. Resistance of enzymes to low temperatures. The re- 

 searches reviewed below demonstrate that the following enzymes 

 survive exposure to low temp. and again exert their usual catalytic 

 power when brought into a suitable environment : — lipase, protease 

 of plants, pepsin, trypsin, rennin, thrombin, zymase, invertase, mal- 

 tase, diastase, inulinase, oxidase, peroxidase, catalase, and simple 



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