210 BIOCHEMISTRY OF BACTERIAL LUMINESCENCE 



1. Bacterial luminescence is a respiratory phenomenon that has an 

 absolute requirement for Oo, although luminescence is less sensitive 

 to low [O2] than respiration (Eymers and van Schouwenburg, 1937; 

 Shoup, 1929). 



2. Tliis "light respiration" is essentially cyanide insensitive ( Harvey, 

 1920), although various organic compounds, particularly naphtho- 

 quinones, are strongly inhibitory to it (Spruit and Schuiling, 1945; 

 McElroy and Kipnis, 1947). 



3. Ultraviolet light inhibits luminescence and shows a discrete "in- 

 activation spectrum" (Gerretsen, 1915). 



4. The light emitted is blue-green in color, showing a band with a 

 maximum at ca. 500 millimicrons for a number of species investigated 

 (Spruit-van der Burg, 1950). 



5. The yield of luminescence/02 consumed is ca. 1/100 to 1/1000 

 (van Schouwenburg and Eymers, 1936). 



6. Luminescence shows a temperature dependence similar to that 

 of many other respiratory processes (Johnson et al., 1942). 



7. Pressure-temperature studies indicated that the luminescent sys- 

 tem behaves as a typical protein enzyme ( Johnson, 1947 ) . 



8. Until recently, attempts to extract the system and demonstrate 

 a luciferin-luciferase reaction in vitro have been unsuccessful or not 

 capable of confirmation ( Harvey, 1952; Gerretsen, 1920; Korr, 1935 ) . 



Our success in obtaining brightly luminous extracts (Strehler 

 1953a), since confirmed in other laboratories (McElroy et al., 1953), 

 must be ascribed to the superior light detecting equipment we em- 

 ployed which enabled us to follow very dim luminescences (Strehler, 

 1951), quantitatively and for considerable periods, and to the fact 

 that high purity biochemical reagents and intermediates are now 

 available cheaply and in quantity. 



Thus, the quantum counter of nearly ultimate sensitivity and low 

 noise level made it possible to measure the dim luminescence ex- 

 hibited by acetorized extracts of A. fischeri while available supplies of 

 DPN, FMN, etc. made it possible to study the effects of these com- 

 pounds easily and rapidly. The rapidity with which developments 

 have been forthcoming, the general good fortune which attended 

 critical phases of this work, and the complexity of some of the 

 results have made it difficult to keep interpretation abreast of experi- 



