The linkage of chemical changes in muscle extract

THIS work was started as a result of the first paper of a series by Lohmann [1934] had shown that in dialysed muscle extract adenylic acid reacts with phosphocreatine to give adenylpyrophosphate; Parnas and his colleagues pointed out that muscle deaminase attacks only adenylic acid, not adenylpyrophosphate. They argued therefore from the NH3 inhibition that synthesis of phospho- creatine had taken place at expense of the energy and the phosphate of phospho- glyceric acid breakdown, and had been followed by conversion of adenylic acid into adenylpyrophosphate by Lohmann's reaction. Since that time they [Parnas et al., 1935, 1] have actually demonstrated in this muscle "brei" an increase in phosphocreatine (especially when creatine is added), and an increase in adenyl- pyrophosphate, accompanying the ammonia inhibition. In Parnas's experiments the iodoacetate prevented the breakdown of the carbohydrate of the "brei" by inhibiting the dismutation of dihydroxyacetonephosphate to give glycerophosphate and phosphoglyceric acid [Meyerhof and Kiessling, 1933, 1; Barrenscheen and his colleagues [1935] have also shown that, during the disappearance of phosphoglyceric acid from muscle "brei " or extract, there is an increase in easilyhydrolysable organic P, although, apart from showing some increase in phosphopyruvic acid, they did not identify the compounds formed.