EFFECTS OF PRESSURE 



847 



similar. Therefore, K„^ and K^ will generally change in the same way. If 

 the Michaelis constant is not K^, this, of course, will not necessarily be true. 

 Competitive inhibition will not be changed as much as noncompetitive 

 inhibition upon changing the pressure because of the similar effects on the 

 binding of both substrate and inhibitor. 



TEMP. 



Fig. 15-23. Effects of temperature and jjressure on the activity 

 of yeast /S-friictofuranosidase. A, 1 atm pressure in the absence 

 of inhibitor; B, 1 atm pressure and ,500 vaM urethane; C, 680 

 atm pressure in the absence of inhibitor; and D, 680 atm pres- 

 sure and 500 m3f urethane. (From Johnson et al., 1948.) 



It would seem that the effects of high pressures on simple enzyme in- 

 hibitions would be straightforward and rather easily interpretable. How- 

 ever, the one example we have is not at all simple. The effects of pressure 

 on the uninhibited and urethane-inhibited rates of /?-fructofuranosidase are 

 shown in Fig. 15-23 and on the urethane inhibition in Fig. 15-24 (Johnson 



