The incorporation of radioactive phosphate into ATP in glycerinated fibres stretched or released during contraction
(1974) Journal of mechanochemistry & cell motility — Vol. 3, n° 1, p. 55-68 (1974)
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- Authors
Maréchal, Georges 
- Abstract
- Bundles of glycerinated psoas muscles contracted in a solution containing 5 mM ATP-Mg, 1 mM ADP, and 1.67 mM sodium phosphate containing 32P at a specific activity of 20 mC/mmole phosphate. Contractions were isometric, or isometric for 10 sec followed by a stretch or a release, or isotonic with zero load and lasted 13 to 40 sec. They were arrested quickly by freezing the bundle (with cold isopentane) or deproteinizing it with perchloric acid. ATP was separated from inorganic phosphate by a two-step procedure: ATP was first adsorbed on charcoal; a subsequent separation was achieved by thin layer chromatography on cellulose polyethylenimine impregnated. The incorporation of 32P into ATP increased with the duration of the contraction, and with the force held by the fibres. This was clearer when the phenomenon is corrected for the variations in bundle size. Stretched fibres incorporate more 32P into ATP, but this may be explained by the higher tension supported by the fibre. The quantity of the 32P incorporated into ATP was low; the equivalent chemical energy corresponding to this apparent "synthesis" of ATP was only 2 % of the work done on the muscle. We found no evidence to support the hypothesis that mechanical work done on a fibre is used to synthesize ATP.
Citations
Gillis, J. M., & Maréchal, G. (1974). The incorporation of radioactive phosphate into ATP in glycerinated fibres stretched or released during contraction. Journal of mechanochemistry & cell motility, 3(1), 55-68. https://hdl.handle.net/2078.5/214689 (Original work published 1974)