558 CATALASES 



measuring the height to which a column of mercury is raised 

 by the oxygen set free in the reaction, that is, the pressure 

 against which the catalase is able to act. 3 



If the activities of two catalase solutions are to be com- 

 pared the "catalytic power" of each, in the author's opin- 

 ion, should be worked out; this, too, according to Victor 

 Henri, 4 being the only proper basis for comparison of the 

 effective ability of two colloidal metallic solutions. The 

 reaction velocity of hydrogen peroxide cleavage is de- 

 termined according to the equation -^- = K(a - x) , t being the 



time, a the amount of H 2 2 at zero time, x the amount of 

 H 2 O 2 broken up in the time t, and K a constant, expressing 

 nothing more than that the amount of peroxide of hydrogen 

 broken up in any fraction of time is in direct proportion to 

 the amount of H 2 2 at the moment present. A simple cal- 

 culation gives K = i log and determines the value of 



\-j 9i X 



the constant K. If in addition it is desired to obtain the 

 "catalytic capacity, " the relation of the amount of the 

 metallic solution employed to the quantity of hydrogen 

 peroxide must also be taken into account. 



The reaction kinetics of catalase action, in which we 

 have an example of a "reaction of the first class, " according 

 to Senter, has been the subject of study at the hands of quite 

 a number of authors. 5 It is, however, impracticable to 

 enter into this subject here, as it falls entirely in the domain 

 of physical chemistry. There are, too, a number of studies 

 concerned with the analogies in the action of the catalases 

 and of colloidal metals. According to Liebmann platinum 

 catalase may perhaps be thought of as consisting primarily 

 of a labile oxygen combination of platinum, which then in- 

 duces the separation of the peroxide of hydrogen (Pt 2 + 



3 W. Lob and P. Mulzer, Biochem. Zeitschr., 18, 339, 475, 1908. 



4 V. Henri, C. R. Soc. de Biol., 60, 1041, 1906. 



8 Senter, Raudnitz, Lockemann, Thies and Wichern, Issajew, Bredig and 

 Faitelowitz, Euler, Herlitzka, Bach, Iscoveso, Loeb and Mulzer, and others; cf. 

 Literature : Batelli and Stern, 1. c. 



