ANTIGENS AS BIOCATALYSTS 29 



tion of a little catalase at the outset to the reaction system decomposes 

 hydrogen peroxide as soon as it forms, and thus the enzyme can 

 continue functioning for many hours without weakening. 



a. Disproportionality between the Amount of Inorganic Catalysts 

 and the Amounts of Substrates Catalyzed. Following the above 

 discussion regarding the general and qualitative aspect of these proper- 

 ties of catalysts let us now present a few quantitative data. The com- 

 bination of hydrogen and oxygen at ordinary temperature could be 

 brought about by 2.5 ml. of a colloidal solution of platinum containing 

 as litde as 0.17 milligram of platinum, and at the outset the rate of 

 combination was 1.8 ml. of gas per minute. After a period of time dur- 

 ing which 10 liters of gas had undergone combination it was found 

 that the activity of the colloidal solution was still unimpaired (Rideal 

 and Taylor, 1926). The spontaneous slow decomposition of H2O2 can 

 be accelerated by colloidal platinum in a dilution of 1 Mol (194 g. of 

 platinum) in 70,000,000 liters. The presence of 0.000,000,000,000 IN. 

 CUSO4 solution is sufficient to produce a perceptible acceleration 

 of the rate of oxidation of an aqueous solution of sodium sulphite 

 (Titoff, 1903). The oxidation of aniline hydrochloride, in the prepara- 

 tion of aniline black, is carried out in the cold by a solution of potas- 

 sium or sodium chlorate with the aid of metal catalysts, the most active 

 of which is vanadium 'pentoxide, V2O5 of which one part is sufficient 

 for 270,000 parts of aniline and the corresponding amount of chlorate 

 (Sabatier, 1922). 



b. Disproportionality between the Amounts of Enzymes and the 

 Amounts of Substrates Catalyzed. Calculations (Haldane, 1931) 

 show that one molecule of liver catalase (or one trivalent atom of 

 catalase iron) decomposes (2H202->2H20-l-02) 5.42X10^ molecules 

 of H2O2 per second, at 0°C and 10~^ M substrate concentration. 

 Under the same conditions one molecule of plant catalase decomposes 

 1.7X10^ molecules of H0O2 per second. One atom of peroxidase iron 

 decomposes 10^ molecules of H2O2 in one second (Kuhn, Hand and 

 Florkin, 1931). The iron of the cytochrome oxidase (Warburg) mani- 

 fests an activity of about 10^ oxygen molecules per second (Warburg 

 and Kubowitz, 1929); one molecule of saccharase hydrolyzes 7.0X10^ 

 molecules of sucrose per second (Moelwyn-Hughes, 1933); one part 

 of pure solid carbonic anhydrase (HsCOa-^COo+HoO) in 7,000,000 

 parts of solution is sufficient to double the rate of CO2 evolution and 



