Phosphorylysis of Adenosine-triphosphate and Changes of Mechanical Properties of Glycerinated Muscle Fibers

　It is generally known today that glycer inated-muscle fibers are contracted by the addition of adenosinetriphosphate（ATP）and at the same time they dephosphorylate the ATP．But, in this inhomogeneous system, the relation between the mechanical changes and chemical reaction are not sufficiently understood．From the experiments of free contraction of the fiber reported by Mugikura（1）or Bowen and Kerwin（2）, it will be accepted that the rate of dephosphorylation reaches its steady value far before the contraction height reaches its stationary value．