332 IMMUNO-CATALYSIS 



Urease is completely inactivated by formalin; formalinized urease 

 is non-toxic, and produces no antiurease on injecting into rabbits. A 

 few seconds contact with 0.05 N hydrochloric acid destroys it in such 

 a way that immediately after neutralization it does not produce a 

 reaction with antiurease. 



The toxic effect of urease was completely abolished when a rabbit 

 was first given 90 units of antiurease followed three hours later by 90 

 units of urease. A second rabbit similarly treated with antiurease was 

 also protected against 80 units of urease. Two rabbits which did not 

 receive antiurease succumbed within five hours. 



Six two-kilogram rabbits were injected intraperitoneally with 65 to 

 70 units of urease. After one and a half to two hours, the rabbits were 

 totally paralyzed. Each rabbit was then given by ear vein 80 units of 

 antiurease. Four of the rabbits showed immediate improvement, and 

 became normal within one hour; the other two paralyzed rabbits could 

 not be saved. In another experiment, 30 units of antiurease injected 

 into each of two guinea pigs protected them against 1 5 units of urease 

 injected similarly 90 minutes later. The control animal not receiving 

 antiurease died. Hen antiurease serum, like that of immune rabbits, 

 inhibited urease toxicity and protected rabbits from fatal doses of 

 urease. 



The studies by Kirk and Sumner (1931) thus showed that the fatal 

 effect of urease in rabbits and guinea pigs was neutralized by antiurease 

 unit for unit, in a manner similar to toxin-antitoxin neutralization 

 reactions in vitro and in animals. 



3. Antibody Against Penicillinase 



Penicillinase is an enzyme that destroys penicillin (Abraham and 

 Chain, 1940). It is produced by a variety of bacteria (Bondi and Dietz, 

 1944; 1946; Gilson and Parker, 1948). 



Partial purification of pencillinase obtained from Bacillus cereus 

 (Housewright and Henry, 1947a), and a comprehensive study involv- 

 ing the development of a manometric method of assaying penicillinase 

 and penicillin and the kinetics of penicillin-penicillinase reaction 

 (Henry and Housewright, 1947) is reported. Penicillinase is not a cop- 

 per or iron enzyme. It is a protein or has a protein component essential 

 for activity. Neither free amino groups nor sulfhydryl groups were 



