Abstract
Using a technique for determining Ca and Mg based on Schwarzenberg's method of titration with ethylenediamine tetraacetic acid (EDTA), it was found that glycerol-extracted muscle fibers contain on the average 0.58 millimole Ca and 0.55 millimole Mg per kg. muscle. The fibers take up additional Ca or Mg from dilute solutions of these metals, but in KCl solutions, the excess is exchanged for K ions. Inorganic pyrophosphate (PP) removes part of the bound Mg, no Ca; EDTA removes predominantly Ca, but never more than about one-half the total amount. These results are discussed in relation to previous observations on the effects of PP and EDTA on mechanical properties and contractility of extracted muscle fibers. After the partial loss of bound divalent metals, muscle fibers swell in dilute salt solutions; they also contract slightly and become more translucent.
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Selected References
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- BOZLER E. Relaxation in extracted muscle fibers. J Gen Physiol. 1954 Nov 20;38(2):149–159. doi: 10.1085/jgp.38.2.149. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BOZLER E. The effect of electrolytes on the contractile elements of muscle. J Gen Physiol. 1952 May;35(5):703–710. doi: 10.1085/jgp.35.5.703. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BRINK F. The role of calcium ions in neural processes. Pharmacol Rev. 1954 Sep;6(3):243–298. [PubMed] [Google Scholar]
- FRIESS E. G., MORALES M. F., BOWEN W. J. Some further observations on the interaction of EDTA with the myosin-ATP system. Arch Biochem Biophys. 1954 Nov;53(1):311–313. doi: 10.1016/0003-9861(54)90256-8. [DOI] [PubMed] [Google Scholar]
- SZENT-GYORGYI A. Free-energy relations and contraction of actomyosin. Biol Bull. 1949 Apr;96(2):140–161. [PubMed] [Google Scholar]