Rate of Dephosphorylation of Adenosinetriphosphate and the Isotonic and Isometric Contraction of Glycerol-Treated Muscle

¹ From the National Institute of Arthritis and Metabolic Diseases, National Institutes of Health, Bethesda, Maryland

A comparison of the rapidity of shortening in isotonic contraction and the development of tension in isometric contraction of glycerol-extracted muscle fibers was made. Increasing the concentration of magnesium causes shortening and tension to increase in a similar manner. These increases occur over a range of concentration of magnesium which has no effect on the adenosinetriphosphatase activity of the fiber-bundles. Increasing the concentration of calcium causes both isotonic and isometric contraction to decrease while the rate of splitting adenosinetriphosphate is increased. Increasing the concentration of potassium has no definite effect on contraction except above 0.2 m. Between 0.2 m and 0.3 m shortening increases while tension-development decreases. This dissimilarity is probably related to dissolution of the fibers.

This article has been cited by other articles:

				W. J. Bowen and L. Mandelkern Glycerinated Muscle Fibers: Relation between Isometric Tension and Adenosine Triphosphate Hydrolysis Science, July 16, 1971; 173(3993): 239 - 240. [Abstract] [PDF]