48 



Scientific Proceedings (31). 



19 (357) 



The mechanical destruction of pepsin. 

 By A. 0. SHAKLEE and S, J. MELTZER. 



[From the Rockefeller Institute for Medical Research.'] 



At various times since 1884, one of us (M.) has studied the 

 effects of shaking upon living cells, such as red blood corpuscles, 

 bacteria, and arbacia eggs. Those experiments led to the general 

 conclusion that shaking, by virtue of the mechanical factor, exerts 

 a profound influence upon living organisms. In the present series 

 of experiments we intend to investigate the changes which shaking 

 may produce in the action of ferments. We began with the study 

 of pepsin, the determination of which is greatly facilitated by several 

 recently described reactions. 



Solutions of pepsin, partly filling long bottles, were shaken at 

 room temperature and at a temperature of 33° C. for periods of 

 different lengths, by means of shaking machines. Our results 

 which we state here very briefly are unmistakable. Shaking under 

 these conditions destroys pepsin. Even short periods greatly 

 diminish its strength. If shaken long enough it is completely 

 destroyed. The temperature has a marked influence upon the 

 rate of destruction. Higher temperatures hasten the destruction. 



That the effect is not due to oxidation was proved by substi- 

 tuting for the air in the bottles, hydrogen, carbon dioxide or 

 oxygen. There was no appreciable difference in the results. 



It was also shown experimentally that the destruction was not 

 brought about by any rise of temperature caused by the shaking. 

 Maximum thermometers were fixed in the bottles perpendicular 

 to their long axes, that is, perpendicular to the direction of shak- 

 ing : in no case did the thermometer inside register as much as a 

 degree higher than the thermometer outside. 



We have also found that the degree of shaking which occurs 

 in the animal body is sufficient to reduce the activity of pepsin. 

 This was determined by introducing a small bottle containing a 

 solution of pepsin into a dog's stomach through an esophageal 

 fistula and permitting it to remain there for 24 hours or longer. 

 The pepsin strength was diminished as much as 40 per cent, com- 



