BERNARD L. STREHLER 



215 



co-workers (1953), who were able, through combined acid precipi- 

 tation and ultraviolet treatment, to obtain a flavin-free system which 

 exhibited luminescence only in the presence of added flavin mono- 

 nucleotide. The effect of flavin is illustrated in Fig. 4. These workers 

 also reported the preliminary finding of a component in the extracts 

 which they called bacterial luciferin. As is the case with firefly lucif- 

 erin, this component was destroyed during luminescence. 



-I- 



3 5 



CONCN. OF FMN ( moles x lO"^) 



Fig. 4. Effect of FMN concentration on bacterial extract luminescence. To 0.6 

 ml oi a 27c (2 g acetonized powder/ 100 H2O, resolved by precipitation at 

 pH 4-4.5), aqueous extract of A. jischeri in 0.1 M phosphate buffer (pH 

 7.0) was added 500 /xg of DPNH2 and 36 Mg of pabnitic aldehyde. Total 

 vol., 2 ml FMN added as indicated. 



