788 



15. EFFECTS OF VARIOUS FACTORS ON INHIBITION 



(Fig. 15-11). These results have led to the hypothesis that sulfanilamide 

 is a type I inhibitor and that urethane is a type II inhibitor. The large 

 changes in heat content {AH between — 56 and — 70 kcal/mole) and 

 entropy (JS between — 165 and — 204 cal/mole /degree) for the urethane 

 inhibition have been interpreted in terms of the reversible denaturation 

 induced by this substance (Johnson et al., 1942 b). 



100 



Fig. 15-11. Effects of temperature on the luminescence 



of P. phosphoreuni in the absence and presence of 



urethane, showing the shift in the Tg^t produced by 



urethane. (From Johnson et al., 1945.) 



The luminescent system in the living organism is complex and involves 

 not only the enzymes, cofactors, and luminescent substances required di- 

 rectly for the emission of radiation, but also occasionally high-energy phos- 

 phate compounds and the oxidative pathways supplying them. Indeed, the 

 bacterial luminescent pathways have not yet been completely delineated. 



