260 



LIGHT AND LIFE 



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5 14 

 TIME IN HOUR S 



Fig. 2. Upper: Tracings of automatically recorded curves showing the lumines- 

 cent reaction oi iucifcrase and partially oxidi/cd liicifcrin in the presence and 

 absence of ascorbic acid. The latter evidently reduces re\ersibly oxidized liici- 

 fcrin, and thereby prevents the delayed dim luminescence which may otherwise 

 complicate the Imuincscent reaction. 



Lower: Ifnoxidi/.cd kiciferin remaining after \arious times of incubation, at 

 26°C and pH S.6. in the presence of (a) 0.01 M ascorbic acid, (b) 0.001 M ascorbic 

 acid, and (c) no ascorbic acid. It is clear that ascorbic acid effectively protects 

 lucifcrin against non-luminescent oxidation. 



the equation lor a simple first-order reaction, although the equation 

 will fit the other limiinescence curve exactly. 



1 he use ol such a reductant a.s ascorbic acid shoukl do much to 

 simplily measinemcnt.s ol the kinetics of the Cypridina lucifcrin- 

 liuilerase reaction, by abolishing the conijilicating effects often pro- 

 duced by the ])rcscn(0 of reversibly oxidi/cd lucifcrin. Tn addition. 



