12G 



PHYiSIOLOGY OF BACTERIA 



The rate of decomposition of the substrate (sahciii) is proportional 

 to the concentration of unchanged substrate (a — x), and also pro- 

 portional to the concentration of the enzyme, E. 



k ■ E(a - x) 



Fig. 16. — Influence of temperature and time upon enzyme action; the 

 percentage of salicin decomposed by emulsin at different temperatures during 

 the first 5 hours. 



This equation is correct for any constant temperature. If the tem- 

 perature changes, the general law remains unchanged, only k reveals 

 itself as a function of the temperature. This is expressed l)y the 

 van t'Hoff rule 



koc 



T-To 

 T-To 



