ANTIBODIES AGAINST RESPIRATORY ENZYMES 



383 



immune serum added to the complete reaction system at the beginning 

 of the experiment or after the reaction has started, completely inhibits 

 the activity of hexokinase. 



Hexokinase was prepared from Fleischmann's baker's yeast accord- 

 ing to the method of Kunitz and McDonald (1946) and the dialyzed 

 "0.72" fraction was used for immunization and for activity tests with 

 various sera (for details, see original literature). The method used for 

 the measurement of hexokinase activity consisted of manometric 

 measurement of carbon dioxide evolved according to the method Colo- 

 wick and Kalckar (1943) and Berger, et at. (1946) adapted to our 

 conditions. 



Ixximu-iiz seram, 0-2 ml. 

 Immane scram. 4 ml. 



Minutes • 



-r — I — I — I — I — I — I — ' — I — ' ' ' I 

 ZO 40 60 80 100 120 140 



Fig. I . Inhibitory effect on yeast hexokinase by homologous rabbit antiserum 

 added before the reaction had started. 



