]16 CHEMISTRY OF BACTERIA AND THEIR PRODUCTS 



on bouillon. There does not seem to be any important relation be- 

 tween enzj'me production and pathogenicity.*^" 



In general, bacterial proteolytic enzymes resemble trypsin more 

 closely than they do pepsin, acting best in an alkaline medium; but 

 the enzymes extracted from bacterial cultures are very feeble as com- 

 pared with pancreatic trypsin. It is probable that there are several 

 distinct proteolytic enzymes in bacterial cells, gelatinase being a dis- 

 tinct protease (Jordan)."'' Abbott and Gildersleeve found that the 

 gelatin-dissolving enzyme of bacteria resists a temperature of 100° C. 

 for as long as fifteen to thirty minutes, but Jordan found that the 

 reaction of the medium modified greatly this heat resistance. 

 Schmailowitsch '^^ states that some bacteria produce an enzyme acting 

 in acid medium upon gelatin but not upon albumin, and this enzyme 

 carries the digestion only as far as the gelatin-peptone stage, whereas 

 the enzymes acting in an alkaline medium carry the splitting through 

 to leucine, tyrosine, etc. Kendall and Walker ^^-'^ state that the pro- 

 teolytic enzymes of B. pruteus are not formed when the bacteria have 

 enough carbohydrate supplied so that they need not depend on pro- 

 teins for their energy requirements; deaminization is independent of 

 proteolysis and represents intracellular enzj^me action. Plenge *" 

 suggests that there is a special enzyme digesting nucleoproteins. 

 Bacteria are able to split nucleic acids and to convert amino-purines 

 into oxypurines, but they do not carry the oxidation to uric acid; 

 putrefactive bacteria can slowly destroy uric acid (Schittenhelm),*^ 

 and B. coli destroys purines.*'^^ 



Cacace *^ investigated the splitting products of gelatin and coagu- 

 lated blood when digested by B. anthracis, Staph, pyogenes aureus, 

 and Sarcina aurantiaca, and found that proteoses and peptone are 

 produced, which disappear in the later stages of digestion. Rettger *^ 

 found leucine, tyrosine, tryptophane, as well as phenols, skatole, in- 

 dole, aromatic oxy-acids, and mercaptan, among the products of bac- 

 terial decomposition of egg-albumen and meat; proteoses and pep- 

 tones appear in the early stages, but later disappear, as also eventu- 

 ally do the leucine, tyrosine, etc. Choline has also been found in the 

 l)roducts of autolysis.^" 



The digestive power of the filtrates of cultures and of killed bac- 

 teria is far less than that of the living bacteria (Knapp).^^ Strepto- 



4«a Rosenthal and Patai. Cent. f. Bakt., 1014 (7.'?), 400; (74), 3011. 

 4-Ji) Corroborated bv Bertiau, Cent. f. Bakt.. 1914 (74), 374. 

 4.-. Abst. in Biocliein. Centr., 1903 (1), 230; see also DeWaele. Cent. f. Bakt., 

 1905 (39), .353. 



45a.l,Hir. Infect. Dis.. 1915 (17), 442. 

 40Zeit. f. i.livsiol. C'liem., 1903 (39), 190. 



47 Zeit. physiol. Ciiem., 190S (57). 21. 



4Ta Siven, Zeit. phvsiol. Chem., 1914 (91), 33(). 



48 Cent. f. Bakt.. 1901 (30), 244. 

 40Amer. Jour, of Physiol., 1903 (8), 284. 



r.o KiitHcher and Loliiiiann, Zeit. plivsiol. Ch(>ni., 1903 (39), 313. 

 M Zeit. f. lleilk. (Cliir. Abt.) 1902 (23), 230. 



