Dephosphorylation in muscle extracts

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Abstract
An aq. extract of a powder made by precipitating fresh rabbit muscle extract with acetone and drying contained both hexosediphosphatase (which split hex. di-phosphate into hex. monophosphate and inorganic P) and inorganic pyrophosphatase but no adenylpyrophosphatase. Such an. extract did not dephosphorylate adenylpyrophosphate (A.T.P.), but was found to dephosphorylate phosphoglycerate (via phosphopyruvate) though not creatinephosphate if small amts. of A.T.P. and Mg were added. [image]/25 fluoride inhibited the reaction but not [image]/250 iodoacetate. Arsenate greatly activated the dephosphorylation of phos-phoglycerate in the presence of A.T.P., Mg and cozymase but since this was inhibited both by F and by iodoacetate it was perhaps of a different character. The possibility of the dephosphorylation of phosphopyruvate involving not merely a simple transfer of the phosphate to adenylic acid but being part of a series of connected reactions was therefore evident. No satisfactory explanation however has been found for the mechanism of the reaction.