274 



INTRACELLULAR LUMINESCENCE 



perature activity curves can be computed for various pressures. In 

 order to obtain a close fit to the data, however, it is necessary to take 

 into account a temperature dependence of aV* and of AV respectively 

 (Fig. 6), showing again that the simple theory does not include all 

 the reactions that are of importance. It is interesting to note ( Fig. 6 ) 

 that the maximum intensity of luminescence remains practically the 

 same at different pressures, but the temperature at which the maxi- 



0.00324 0.00330 0.00336 0.00342 0.00348 0.00354 0.00360 0.00366 



Reciprocal of the absolute temperature 

 Fig. 6. The brightness of luminescence in P. phosplioreum as a function of tem- 

 perature at three different hydrostatic pressures. The points represent data 

 from experiments by Brown, Johnson, and Marsland (1942). The smooth 

 curves were calculated by Eyring and Magee (1942). (From Johnson, 

 Eyring, and Polissar, 1954, courtesy of John Wiley & Sons.) 



mum intensity occurs is higher under increased than at atmospheric 

 pressure. 



Although data pertaining to the influence of pressure on the re- 

 versible denaturation of isolated enzyme systems are still scarce, there 

 is evidence that highly purified trypsin, with casein as substrate, un- 

 dergoes a reversible, thermal denaturation accompanied by a consid- 

 erable volume increase of reaction (Fraser and Johnson, 1951). 



