The adenosinetriphosphatase activity of myosin preparations

Abstract

ft has been known for many years that muscle contraction is accompanied by appearance of equivalent amounts of inorganic phosphate and free creatine, creatinephosphate disappearing. Until the work of Lohmann [1934] using muscle extract, this process was regarded as an enzymic hydrolysis of creatinephosphate, going on with liberation of energy. But Lohmann showed that the breakdown of creatinephosphate is a composite process, requiring the presence in the extract of adenylic acid and adenosinetriphosphatase:(I) 2 creatinephosphate + adenylic acid -* 2 creatine + adenosinetriphosphate adenosinetriphosphate -+ adenylic acid + 2H3PO4 .

Studies on the Anomalous Viscosity and Flow-Birefringence of Protein Solutions

“…Preparation of Adenosinetripkosphate.--Adenosinetriphosphate was prepared from rabbit or horse muscle by a modification of themethod of Lohmann (1931) as described by D. M. Needham (1942). In some cases the ATP was further purified as described by Kerr and Seraidarian (1941).…”

“…for 20 minutes before the addition of ATP, the fall of/~ was reduced from 50 per cent to 26.5 per cent, the return to the original value was completed in 1 hour, and the phosphorolysis inhibited 62 per cent. Since we know (D. M. Needham, 1942;Bailey, 1942) that Ca'. greatly activates adenosinetriphosphatase, a better way of inactivating the enzyme would be to free it entirely from this ion, perhaps by dissolving it as a sol in oxalate and vigorously centrifuging, but we have not so far succeeded in experiments along this line3 It will, however, be seen from Table X that the return time with CaITP is shorter than with NaITP.…”

“…IH D. M. Needham, 1942), and shortly afterwards by Szent-Gyrrgyi and Banga, 1941;Edsall and Singher, 1941;Bailey, 1942). Its great importance lies in the following facts.…”

“…Although some ATP is broken down by transfer of phosphate to hexosemonophosphate (Neuberg ester) (by an enzyme not present in the myosin fraction of the proteins) this also probably liberating free energy, the quantitatively largest part of its breakdown occurs by splitting off of free phosphate under the infuence of the enzyme adenosinetriphosphatase (D. M. Needham, 1942). It was considered of interest, therefore, to give careful study to the effect of ATP on the flow-birefringence and anomalous viscosity of myosin.…”

The synthesis of nicotinuric acid by rat-kidney preparations

“…The dibarium salt of adenosine triphosphate (ATP) was prepared by the method of Needham (1942) and converted into monobarium ATP (Kerr, 1941). Foruse,solutionsofpotassiumATPwerepreparedby removing the barium with Amberlite IR-100 (H form) and neutralizing to pH6-8withKOH.…”