58 BIOCHIMICA ET BIOPHYSICA ACTA VOL. 4 (1950) 



SOME FACTORS INFLUENCING THE CONTRACTILITY OF A 

 NON-CONDUCTING FIBER PREPARATION* 



by 



SAUL KOREY** 



Department of Neurology, College of Physicians and Surgeons, 

 Columbia University New York, N.Y. (U.S.A.) 



INTRODUCTION 



One of the most important contributions of Otto Meyerhof was the discovery 

 of the high energy which may be contained in phosphorylated compounds. Following 

 the description of phosphocreatine (phosphagen) by Fiske and Subbarow^ and Eggle- 

 TON AND Eggleton^, Meyerhof found, in 1927, that the enzymatic decomposition of 

 this compound is connected with the liberation of a large amount of heat^. The energy 

 released is about 10 000 to 12000 g calories as compared with 2000 to 3000 of other 

 phosphorylated compounds, e.g., hexose mono- and diphosphate, pentose and triose 

 phosphate and other esters, i.e., all those compounds where the phosphate is linked to 

 an alcoholic hydroxyl. Meyerhof found a similar high energy in argininephosphate 

 which in many invertebrates takes the place of creatinephosphate*. A few years later, 

 when in his laboratory, Lohmann had isolated adenosinetriphosphate (ATP) from 

 muscle, Meyerhof^ showed that about 24000 g calories are released by the breakdown 

 of ATP to adenosinemonophosphate (AMP). This is about the same amount of energy 

 for each of the two P as that derived from the P of phosphocreatine. Soon afterwards, 

 two more phosphorylated compounds, intermediates in glycolysis, were found to be rich 

 in energy: phosphoenol pyruvic acid^ and 1.3-diphosphoglyceric acid, isolated by Nege- 

 LEIN AND Bromel in Warburg's laboratory''. The great significance of Meyerhof's 

 discoveries of energy-rich phosphates for the understanding of intermediate metabolism 

 and the far reaching implications have been reviewed in this country by Lipmann^ 

 and Kalckar^. 



Among all the energy rich phosphorylated compounds, ATP plays a special role. 

 Originally the study of this compound was limited to the glycolytic cycle. More recent 

 studies, however, have shown that ATP has a more general importance, as the source of 

 energy in intermediate cellular reactions, as e.g., acetylation (Nachmansohn^*^), urea for- 

 mation (RatnerII) and many others. Although the essential role of ATP in intermediate 

 metabolism becomes continuously more evident, its function in the muscle cell in which 

 it was first discovered and studied is still one of the most challenging problems to biolo- 

 gists. From the work of Meyerhof and his associates, it appeared likely that ATP was 

 involved in the primary changes of the protein during muscular contraction. No other 



* This investigation was supported by a research grant from the Division of Research Grants 

 and Fellowships of the National Institutes of Health, U.S. Public Health Service. 

 ** Senior Fellow in Neurology, U. S. Public Health Service. 



References p. 6y. 



