In Vivo functioning of creatine phosphokinase in human forearm muscle, studied by 31P NMR saturation transfer

31P nuclear magnetic resonance (NMR) saturation transfer has been used to measure enzymatic flux through the creatine phosphokinase reaction in the direction of ATP synthesis in the human forearm muscle flexor digitorum superficialis. Modification of the ratio method for measurement of spin‐lattice relaxation (R. Freeman, H. D. W. Hill, and R. Kaptein, J. Mags. Reson. 7, 82 (1972) was tested and used to appreciably shorten the duration of the measurement. Under conditions of steady state work intracellular pH decreased slightly by 0.06 units and the spin‐lattice relaxation time of phosphocreatine in muscle was unchanged, while flux from phosphocreatine to ATP was 64 ± 10% of the resting value. This is contrary to the increase in flux of 155% predicted from previous saturation transfer studies carried out in vitro on rabbit skeletal muscle creatine phosphokinase using metabolite concentrations to mimic those in vivo (E. A. Shoubridge, J. L. Bland, and G. K. Radda, Biochim. Biophys. Acta 805, 72 (1984). This discrepancy could be accounted for by an underestimation of the ADP concentrations to which the enzyme is exposed due to inaccurate assumptions about the total metabolite concentrations, or possibly by compartmentation of creatine phosphokinase and its reactants. © 1989 Academic Press, Inc.

[1]  M. Weiner,et al.  31P NMR saturation transfer measurements of phosphorus exchange reactions in rat heart and kidney in situ. , 1986, Biochemistry.

[2]  K Uğurbil,et al.  Measurement of an individual rate constant in the presence of multiple exchanges: application to myocardial creatine kinase reaction. , 1986, Biochemistry.

[3]  E. Shoubridge,et al.  Regulation of creatine kinase during steady-state isometric twitch contraction in rat skeletal muscle. , 1984, Biochimica et biophysica acta.

[4]  M J Kushmerick,et al.  A simple analysis of the "phosphocreatine shuttle". , 1984, The American journal of physiology.

[5]  G. Radda,et al.  A comparison of 31P-NMR saturation transfer and isotope-exchange measurements of creatine kinase kinetics in vitro. , 1984, Biochimica et biophysica acta.

[6]  R G Shulman,et al.  NMR studies of enzymatic rates in vitro and in vivo by magnetization transfer , 1984, Quarterly Reviews of Biophysics.

[7]  J. Ackerman,et al.  NMR T1 measurements in inhomogeneous B1 with surface coils , 1983 .

[8]  P J Geiger,et al.  Compartmentation of mitochondrial creatine phosphokinase. I. Direct demonstration of compartmentation with the use of labeled precursors. , 1982, The Journal of biological chemistry.

[9]  D. Gadian,et al.  A 31P-NMR saturation transfer study of the regulation of creatine kinase in the rat heart. , 1982, Biochimica et biophysica acta.

[10]  E. Shoubridge,et al.  31P NMR saturation transfer measurements of the steady state rates of creatine kinase and ATP synthetase in the rat brain , 1982, FEBS letters.

[11]  S Holm,et al.  Energy metabolism in relation to oxygen partial pressure in human skeletal muscle during exercise. , 1981, The Biochemical journal.

[12]  P J Geiger,et al.  Transport of energy in muscle: the phosphorylcreatine shuttle. , 1981, Science.

[13]  D. Wilkie,et al.  The activity of creatine kinase in frog skeletal muscle studied by saturation-transfer nuclear magnetic resonance. , 1981, The Biochemical journal.

[14]  S. Bessman,et al.  Intimate coupling of creatine phosphokinase and myofibrillar adenosinetriphosphatase. , 1980, Biochemical and biophysical research communications.

[15]  R. Nunnally,et al.  Adenosine triphosphate compartmentation in living hearts: a phosphorus nuclear magnetic resonance saturation transfer study. , 1979, Biochemistry.

[16]  R. Veech,et al.  Effects of pH and free Mg2+ on the Keq of the creatine kinase reaction and other phosphate hydrolyses and phosphate transfer reactions. , 1979, The Journal of biological chemistry.

[17]  V. Saks,et al.  Role of creatine phosphokinase in cellular function and metabolism. , 1978, Canadian journal of physiology and pharmacology.

[18]  E. Newsholme,et al.  The role of creatine kinase and arginine kinase in muscle. , 1978, The Biochemical journal.

[19]  I. R. Peat,et al.  The experimental approach to accurate carbon-13 spin-lattice relaxation measurements , 1975 .

[20]  D. I. Hoult,et al.  Observation of tissue metabolites using 31P nuclear magnetic resonance , 1974, Nature.

[21]  E. Hultman,et al.  Glycogen, glycolytic intermediates and high-energy phosphates determined in biopsy samples of musculus quadriceps femoris of man at rest. Methods and variance of values. , 1974, Scandinavian journal of clinical and laboratory investigation.

[22]  H. Eppenberger,et al.  A protein that binds specifically to the M-line of skeletal muscle is identified as the muscle form of creatine kinase. , 1973, Proceedings of the National Academy of Sciences of the United States of America.

[23]  John S. Leigh,et al.  A new method for measuring longitudinal relaxation times , 1973 .

[24]  Ray Freeman,et al.  An adaptive scheme for measuring NMR spin-lattice relaxation times , 1972 .

[25]  John L. Markley,et al.  Spin‐Lattice Relaxation Measurements in Slowly Relaxing Complex Spectra , 1971 .

[26]  Ray Freeman,et al.  Fourier Transform Study of NMR Spin-Lattice Relaxation by , 1971 .

[27]  S. Forsén,et al.  Study of Moderately Rapid Chemical Exchange Reactions by Means of Nuclear Magnetic Double Resonance , 1963 .

[28]  T. Brown,et al.  Application of 31P-NMR spectroscopy to the study of striated muscle metabolism. , 1982, The American journal of physiology.

[29]  D. Gadian,et al.  31P NMR IN LIVING TISSUE: THE ROAD FROM A PROMISING TO AN IMPORTANT TOOL IN BIOLOGY , 1979 .