PHOSPHORYLATION OF R. ruhrum 



305 



TABLE I {Continued) 



Substance 



Final cone, 

 (inoles/liter) 



Remarks 



Diphosphop^'ridine nucleotide 



(DPX) 



Triphosphopyridine nucleotide 



(TPN) 



Cytochrome c (mammalian) 



Cjtochrome c 



+ DPN 



Potassiimi fluoride (KF) 



Hydroxylamine (XH2OH) 



Gas phases other than helium: 



2.5 X 10-* 

 2.5 X lO-" 



.2 X 10-5 

 .2 X 10-5 

 .5 X 10-" 

 ,0 X 10-2 



0.14 



In crude preparations KF slightlj' 

 reduces the rate of orthophosphate 

 release in the dark. This effect does 

 not influence appreciably the net 

 rate of light-induced phosphoryl- 

 ation at saturating light intensi- 

 ties. 



Prepared from XH2OHHCI by 

 neutralization with KOH immedi- 

 ately before addition to experi- 

 mental vessels. 



* Control rates do not differ from 

 those in the experimental systems 

 by more than ±5%. 



** Alkaline pyrogallol in side arm. 

 Shaken in the dark for V2 hour be- 

 fore illumination. 



*** Rates the same in red light 

 (red filter with cut off at 617 m/u) 



as in w^hite 

 lamps). 



light (incandescent 



washed preparation only when, in addition to orthophosphate and 

 ADP, a magnesium salt is added and traces of a substance like suc- 

 cinate, lactate, etc. (4), or traces of reduced DPN. It is suggested 

 that these substances activate the system by reducing a component 

 of the electron, or hydrogen, carrier system (C, CH in Fig. 3) 

 which is capable of coupling with a phosphorylating system (P, Fig. 

 3). It is assumed that in the absence of a reduced carrier (CH) the 



