CHAPTER III 

 BIOCHEMICAL FEATURES 



The behavior of Pneumococcus toward proteins, fats, and carbo- 

 hydrates; acid production; oxidizing and reducing action; and 

 the formation of peroxide, methemoglobin, hemolysin, hemotoxin, 

 and alleged endotoxin. 



The pneumococcal cell is charged with a complement of en- 

 zymes capable of destroying it as well as certain extracel- 

 lular substances upon which they are allowed to act. The living or- 

 ganism and sterile extracts made from it can digest proteins, split 

 lipids, and invert and ferment carbohydrates. 



Proteolysis, Lipolysis, and Carbohydrate Fermentation 



PROTEOLYSIS 



Rosenow 1169 was probably the first to express the opinion, based 

 on experimental evidence, that Pneumococcus contained a proteo- 

 lytic enzyme capable of splitting its inherent protein into a highly 

 poisonous substance and to demonstrate the proteolytic action of 

 Pneumococcus. Extracts of virulent pneumococci made in sodium 

 chloride solution and filtrates of broth cultures hydrolyzed the 

 proteins contained in heated ascites-meat broth and, to a lesser 

 degree, those of heated serum. The extracts did not attack egg- 

 white or pure casein. The enzyme appeared to be more resistant to 

 heat and to long standing in broth filtrates than in salt solution. 

 Heating at 60° reduced the enzymatic action of the filtrates by 50 

 per cent, and almost completely destroyed the activity of the saline 

 extracts. 



In 1920, Avery and Cullen 38 gave a still more detailed demon- 

 stration of the proteolytic action of Pneumococcus. By dissolving 

 living cocci in bile or sodium cholate, or by allowing them to auto- 



