266 IMMUNO-CATALYSIS 



tion of amino nitrogen; and (d) the decrease in viscosity. On the basis 

 of careful measured results he arrived at the conclusion that fibrinolysis 

 is incident to proteolysis of the fibrin molecule, and that proteins other 

 than fibrin or fibrinogen can be digested. 



Christensen and MacLeod (1945) reported that in the completion 

 of the digestion of casein by serum protease there are left linkages 

 which are split by trypsin. On the other hand, serum protease does not 

 produce further hydrolysis of casein which has already been acted 

 upon by trypsin, showing further differences between these proteolytic 

 enzymes. Kaplan (1946) likewise pointed out that the streptococcal 

 serum protease system differs in specificity from the enterokinase- 

 trypsinogen system. Streptococcal factor did not activate trypsinogen, 

 nor was the serum protease activated by enterokinase. Jablonowitz 

 (1939) reported that following the action of fibrinolytic agent fibrino- 

 gen underwent alteration in its serological property. (See further Mor- 

 rison (1947), and Edsall, et at. (1947) concerning the properties of 

 fibrinogen.) 



c. Distribution of Bacterial Fibrinolytic Factor. Fibrinolytic factor 

 is reported by Tillett (1938) to be most widely elaborated by the 

 strains of Streftococcus hemolyticus, particularly by the types belong- 

 ing to Lancefield's Group A. It is elaborated also by Groups C and G; 

 strains belonging to Group B, D, E, F and Streptococcus viridans are 

 reported not to elaborate this factor. According to Tillett and Garner 

 (1933) and Tillett (1935, 1938), the production of this factor is 

 specific for hemolytic streptococci. However, the following findings 

 show that this factor is elaborated by other streptococci and species of 

 bacteria. Neter and Witebsky (1936) studied the effect of the concen- 

 tration of carbohydrates in meat infusion broth on the production of 

 fibrinolytic factor. They reported that the production of this factor by 

 hemolytic streptococci may depend upon the glucose concentration, 

 as well as the particular strain, and that there is no definite relationship 

 between the production of the factor and the type of sugar used (glu- 

 cose, mannite, salicin and lactose). They found that 31 of 40 strains 

 of hemolytic streptococci, 35 of 47 strains of Stre^ptococcus viridans, 

 as was also shown by Tunnicliff (1936), produced the fibrinolytic 

 factor. 



All of the 31 strains of enterococcus (streptococcus fermenting 

 aesculin, a glucoside from horse chestnut) were found to produce the 



