Experiments with Bacterial Enzymes 



M3 



The following facts constitute further and apparently incontrover- 

 tible evidence that the hemolytic and gelatinolytic substances are, at 

 least in a number of bacterial filtrates, entirely distinct. While it is 

 true that the potency of gelatinase in some cases is not entirely 

 destroyed by heating to ioo° C. for lo to 15 minutes (B. pyocyaneus 

 and B. prodigiosus), it is also true that heating for 30 minutes at 110° C. 

 destroys completely all the power of these filtrates to liquefy gelatin, 

 but leaves absolutely intact their hemolytic power. In the second 

 place, certain filtrates which possess marked ability to liquefy gelatin 

 may be entirely devoid of hemolytic power. A single instance may 

 be given. A seven-months-old culture of B. prodigiosus in asparagin- 

 phosphate-sulphate-sucrose solution yielded a filtrate, 0.05 c.c. of 

 which liquefied a tube of gelatin completely in 16 hours at 37.5°. 

 Such a solution has some osmotic action on dog corpuscles, but the 

 addition of o . 4 per cent NaCl renders it isotonic, although not affect- 

 ing its power to liquefy gelatin. The filtrate is then strongly gelat- 

 inolytic, but has no hemolytic effect on dog or rabbit corpuscles, 

 even when 0.5 c.c. is used. 



Other examples may be presented in tabular form : 



Filtrate 



Gelatinolvsis 



Hemolysis (Dog 

 Corpuscles) 



From 3 months' old 

 broth culture — 



f Sp. Finkler-Prior 



B. amyloruber 



From 7 mos.' old broth culture — B. Pyocyaneus . 



0.8 c.c. 

 o. I 

 0.05 

 °-5 



o. 5 



None 



Complete 

 None 



Complete 



None 



\'ery strong 



It is true, then, (i) that certain hemolytic filtrates, heated at 110° 

 may be robbed completely of their power to liquefy gelatin without 

 evincing any diminution of hemolytic power {B. pyocyaneus, B. 

 prodigiosus); (2) that a bacterial filtrate may possess gelatinolytic 

 power without being able to produce any hemolysis whatsoever {B. 

 amyloruber); (3) that a bacterial filtrate may be strongly hemolytic 

 without possessing any power to liquefy gelatin. 



SUMMARY AND CONCLUSIONS. 



I. There is no evidence that the presence of gelatin in a culture 

 medium leads to any particularly rapid or abundant production of 

 the specific ferment acting upon the gelatin. On the contrar)- other 



