ON THE RELATION BETWEEN TENSION AND ATP IN CROSSSTRIATED MUSCLE

Abstract

A new method of phosphate estimation is described which allows the estimation of the labile phosphate of ATP [adenosine triphosphate] in presence of free phosphate. The method is based on the solubility of phosphomolybdate in butyl alcohol. The quantity of this compound can be measured by its yellow color in butyl alcohol using the blue S 42 filter in the Klett-Summerson colorimeter. First the free phosphate is shaken out as phosphomolybdate by a mixture of ether and butyl alcohol, then the ATP is hydrolyzed and the phosphate liberated, shaken out and estimated. The tension of the psoas muscle after freezing and thawing was measured at different intervals after death. Simultaneously, the ATP concn. was measured. Both were found to decrease parallel. This supports the theory of the muscle being built of functional units composed of actomyosin and ATP.