196 A SYMPOSIUM ON RESPIRATORY ENZYMES 



occurred in definite proportions and in good agreement with the 

 equation: 



CH3 • CO • COOH + HO • PO3H2 + O - CH3 • CO • 

 OPO3H3 + CO2 + H,0 



Recently the formation of a labile phosphate compound could be 

 demonstrated directly by the use of the method with which creatine- 

 phosphate was originally discovered both by Fiske and Subbarow 

 and by the Eggletons. This method consists in reading the develop- 

 ment of the blue color against a standard of inorganic phosphate, 

 the increase in color with time being proportional to the breakdown 

 of the labile phosphate compound. The half-decomposition time of 

 our phosphorylation product (and of acetylphosphate) is about one 

 minute at room temperature. This rapid decomposition of the nat- 

 ural as well as the synthetic product is due not merely to the acidity 

 of the solution but largely to a catalytic effect of molybdate. Re- 

 cently silver fractions containing the labile phosphate have been 

 obtained from trichloroacetic acid extracts. Although, as should be 

 emphasized, pure preparations of the phosphorylation product have 

 not yet been obtained,* the reported results may be taken as fair 

 evidence that the intermediate formed during pyruvic acid oxidation 

 is in fact acetylphosphate. 



REFERENCES 



1. LiPMANN, F., Enzymologia, 4, 65 (1937). 



2. LiPMANN, F., Nature, 143, 281 (1939). 

 OcHOA, S., J. Biol. Chem., 138, 751 (1941). 



3. LiPMANN, F., Advances in Enzymology, 1, 99 (1941). 



4. Negelein, E., and Bromel, H., Biochem. Z., 300, 225 (1939). 



5. LiPMANN, F., Nature, 144, 381 (1939). 



6. LiPMANN, F., J. Biol. Chem., 134, 463 (1940). 



* Since submitting this paper we have succeeded in isolating silver acetyl- 

 phosphate from the impure silver fractions. 



