112 CHEMISTRY OF BACTERIA AND THEIR PRODUCTS 



products of autolysis.^* MoUiard^^ reports that Isaria densa produces 

 large masses of crystals of glycine, even when grown on proteins that 

 contain little or no glycine. 



The digestive power of the filtrates of cultures and of killed bacteria 

 is far less than that of the living bacteria (Knapp).^^ Streptococci 

 digest proteins of exudates feebly, staphjdococci more rapidl}-, and 

 colon bacilli are still more active. He could find no relation between 

 the proteolytic power of the bacteria and the severity of the infection 

 from which they came. Staphylococci can cause coagulation of plasma 

 and then dissolve the coagulum, showing the presence of two enzymes, 

 staphylokinase and fibrinolysi7i (KMnschmidt) .^"^ Sperry and Rettger,^^ 

 however, found that even the most actively putrefactive bacteria are 

 unable to attack or grow upon carefullj^ purified proteins, although 

 the presence of small amounts of amino acids or other available nu- 

 trient makes the proteins available to the bacteria; apparently they 

 must have some nutrient more available than intact protein molecules 

 to enable them to grow sufficiently to produce enough free enzymes to 

 attack the proteins. By virtue of their proteolytic enzymes, filtrates 

 of bacteria that liquefy gelatin also can digest hardened liver, kidney 

 and other tissue elements in vitro the changes resembling those of 

 necrobiosis.^^ 



Oxidizing Enzymes. — Catalase is demonstrable in bacteria, the anaerobic 

 forms showing the least activity (Rywosch),' but practically no species is entirely 

 inactive (.Joi'nsj ;' it may exist as either endo- or ecto-enzyme. B. pi-oteus synthe- 

 sizes catalase even when grown on a simple sj^nthetic medium containing, besides 

 inorganic salts, sodium lactate and alanine or aspartic acid (Jacob^-).^ Certain 

 bacteria and actinomyces exhibit oxidative effects, resembling tyrosi7iase, but such 

 an enzyme could not be extracted by Lehmann and Sano.'' Tsudji,* however, 

 not only observed oxidation of tyrosine, but states furthermore that proteus pro- 

 duces always a d-oxyacid product and subtilis a 1-oxyacid type, regardless of 

 whether they have oxidized d-, 1-, or dl-tyrosine. 



Immunity against bacterial enzymes may be secured as it is against 

 other enzymes. Abbott and Gildcrsleeve^- found that by injections 

 into animals of proteolytic bacterial filtrates which were only slightly 

 toxic, the serum of the animals acquired a slight but specific increase 

 in resistance to the proteolytic enzymes of the filtrates.^ Normal 

 serum contains a certain amount of enzyme-resisting substance. 



»^ Kutscher and Lohmann, Zcit. phvsiol. Chcm., 1903 (39), 313. 



»''Compt. Rend. Acad. Sci., 1918 (167), 7S(i 



"oZeit. f. Ileilk. (Chir. Abt.), 1902 (23), 230. 



0' Zcit. Immunitiit., 1909 (3), 510. 



•■"•.four. Biol. Chem., 1915 (20), 445; Jour. Hact., 1910 (1), 15. 



»'■' Bittrolff, Zicgler's Beitr., 1915 (00), 337. 



• Cent. f. Bakt., 1907 (44), 295. 

 2 Arcli. f. Ilvg., 190.S (07), 134. 



=• Biocliem. Zcit., 191S (SS), 35 and (89), 350. 



< Arcli. f. llyg., 190S (()7), 99. 



' Acta Schoiac Med. Tniv. Kioto, 191S (2), 115. 



• Antigehitiiiase has also been obtained by Bertiau, Cent. f. Bakt., 1914 (74) 

 374. 



