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  • Title: [Determination of two unknown peaks in the 31P magnetic resonance spectrum appearing during the breakdown of high energy phosphates in the ischemic heart and skeletal musculature].
    Author: Keidel WD, Keidel J, Reiman V, Csatary N.
    Journal: Res Exp Med (Berl); 1984; 184(2):73-84. PubMed ID: 6332354.
    Abstract:
    Using the 31-Phosphorus pulsed NMR-technique by FFT information processing it was possible to obtain the following results: The phosphorus compounds were measured as time function in the course of 24 h in isolated skeletal and cardiac muscle of rana temporaria in a dynamic NMR experiment. The shift of the observed resonance lines by increasing intracellular H+ concentration during anoxic conditions will be described in this paper in accordance with the NMR literature. The time course of the beta group of ATP (which is representative for ATP) has been found not to decrease monotonically but rather periodically in a half-hour periodicity until finally a complete fading of ATP in the NMR spectrogram occurs. Besides the resonances described in the literature it was possible to record two additional unknown resonance lines 1.6 and 4.6 ppm apart from the classical alpha- and beta ATP peaks. The peak area of this up to now unknown substance followed a periodic law, regarding the first 2-3 h after preparation. Afterward the concentration dropped to zero. Some shift of the resonance lines of the NMR spectrum could be observed dependent upon the fact that in the muscle cell the ATP normally occurs as a complex with Mg++ ions (MgATP). After separation of Mg++ ions from ATP at low intracellular pH values the resonance lines shifted by some 1-4 ppm. This was tested by test solutions containing MgATP as a complex of free ATP. Although this observation could not sufficiently explain the two as yet unknown lines in the NMR spectra, this result gave rise to further exploration of the phenomenon. To explain the unknown resonance lines, the spectra of the heart and skeletal muscle were compared with that of an adenosine tetraphosphate solution. Based upon the fact that the frequencies of the lines under discussion are identical with those of the adenosine tetraphosphate, one can conclude with a high degree of probability that the as yet unknown lines are originated by adenosine tetraphosphate. If this hypothesis is correct, the concentration of adenosine tetraphosphate could be determined in the order of 1 mM, thus being one third or one quarter of the concentration of the adenosine triphosphate. To give better evidence for the clarification of the newly found substance it will be necessary to record under identical experimental conditions 1H and 13C NMR spectra during the time course of deterioration of the skeletal and cardiac muscle.(ABSTRACT TRUNCATED AT 400 WORDS)
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