PRODUCTS OF METABOLISM l8l 



Autolytic Bacterial Enzymes. A large number of bacteria 

 produce proteolytic enzymes which are capable of digesting 

 other bacterial cells, and also capable of digesting themselves 

 (autolysis). Enzymes of this character are called autolytic. 



It has been noted that in the growth of some species of bac- 

 teria on artificial media that the bacteria increase in numbers 

 for a varying period of time, then gradually decrease. This 

 phenomenon occurs in some cultures of Msp. comma. This 

 fact can only be accounted for by assuming in some cases that 

 the proteolytic enzymes of the cholera bacteria digest them- 

 selves (autolytic) and their neighbors (isolytic). 



Growth proceeds when the autolytic enzymes are removed. 

 In those diseases due to bacteria which produce endotoxins 

 it is probable that these toxic products are liberated from 

 the bacterial cell by the action of autolytic enzymes, by leuco- 

 cytic enzymes, and by the proteolytic enzymes of tissue cells 

 in the vicinity of the diseased area (typhoid, tuberculosis, 

 dysentery, cholera, etc.). It would seem from what has been 

 learned from recent investigations that the autolytic enyzmes 

 are very similar to nuclein in structure. Autolysis of Bac- 

 terium tuberculosis and allied forms progresses very slowly. 

 In time the endotoxins themselves are digested by the 

 proteolytic enzymes. 



Pseudomonas pyocyanea produces a proteolytic enzyme 

 w r hich is heterolytic and furthermore selective in its action. 

 The enzyme produced is decidedly antagonistic to a Bact. 

 anthracis and Bact. diphtherias. It prevents growth abso- 



