COUPLING OF REDUCED PYRIDINE NUCLEOTIDE OXIDATION 



TABLE I 



171 



EiTECT OF Some Inhibitors on Vitamin Kj-Stimulated Oxidation of Glucose- 

 6-Phosphate by Mitochondria and Soluble Cytoplasm 



Additions (+ ) or omissions ( — ) 



Relative oxygen consumption 



Complete system 



+ 2 X 10 ^ m Amytal 

 + I ij.g. Antimvcin A 

 + 10-3 ^i J^C^T 



+ 10 "^ m dicoLimarol 

 — vitamin K., 



100 

 109 



39 

 24 



43 

 31 



Conditions as in Fig. i. Respiration of complete system was 10-12 /^atoms 

 oxygen/20 min. 



minutes 



Fig. 2. Mitochondrial oxidation of extramitochondrial TPNH mediated by 

 DT diaphorase and vitamin K;j. The complete system contained per Warburg 

 vessel 0-5 jLimole TPN, 20 /xmoles glucose-6-phosphate, i unit glucose-6-phosphate 

 dehydrogenase (Sigma), 20 |umoles tris buffer (pH 7-4), 12 /imoles orthophosphate 

 (pH 7-4), 4 /umoles MgCl.^, 2 /tmoles adenosine triphosphate, 24 /tmoles glucose, 

 an excess of yeast hexokinase, 50 /tmoles sucrose, mitochondria from 200 mg. 

 rat liver, o- 01 /nmole vitamin K^,, and an amount of 450-fold purified DT diaphorase 

 (together with i mg. serum albumin) capable of reducing i /^miole vitamin K3 

 per min. Final volume, i o ml. Temperature 2°- Reading begun after 6 min. 

 thermoequilibration. [3] 



1. Complete system. 



2. No DT diaphorase. 



3. No DT diaphorase, no vitamin Kg. 



4. No mitochondria. 



