242 



BIOCHEMISTRY OF BACTERIAL LUMINESCENCE 



1200 X g for 5 minutes to throw down the asbestos, and the reduced 

 flavin supernatant removed with a 1-cc tubercuHn syringe and 0.2 

 cc squirted under 0.6 cc of the bacterial extract containing a small 

 amount of palmitaldehyde. This method is simple and has many 

 advantages for handling solutions of rapidly oxidizable substances. 

 Observation of fluorescence in ultraviolet light indicates that the 

 flavin oxidizes only at the surface of such a solution in contact with 

 air and not in the syringe. 



TABLE IV 



The results of adding various flavins to the crude Gest extract are 

 shown in Table IV. The FMN experiment served as a control to 

 indicate that the extract was active. It will be observed that with the 

 exception of riboflavin phosphate and N-methylalloxazine, practically 

 no luminescence appears with any flavin. Samples of riboflavin from 

 two different sources gave different results. To what extent contami- 

 nants may be responsible for luminescence with riboflavin and with 

 lumichrome is impossible to say. The negative results with the 

 flavoproteins, both of which contain FAD ( flavinadeninedinucleotide ) 

 or an FAD like prosthetic group, should be especially noted. These 

 flavoproteins were lyophilized and kindly supplied by Dr. H. R. 

 Mahler, of the University of Wisconsin Institute of Enzyme Research. 

 It will be most important to test a flavoprotein containing FMN. 



