Chapter

Oxygen Transport to Tissue XI

Volume 248 of the series Advances in Experimental Medicine and Biology pp 687-692

How Phosphocreatine Buffers Cyclic Changes in ATP Demand in Working Muscle

  • C. FunkAffiliated withDepartment of Mechanical Engineering, University of Rochester
  • , A. ClarkJr.Affiliated withDepartment of Mechanical Engineering, University of Rochester
  • , R. J. ConnettAffiliated withDepartment of Physiology, University of Rochester

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Abstract

What is the role of phosphocreatine in energy metabolism of muscle tissue? The various roles that have been proposed over the last 50 years all fall into two categories: spatial transport and storage of high-energy phosphate. We analyse the function of phosphocreatine as a temporal buffer within a muscle cell on the basis of a simple model. Our model is based on the assumption of equilibrium of the creatine kinase reaction
$$Mg.ADP + PCr + {H^ + }Mg.ATP + Cr.$$
Also, all species are allowed to diffuse freely between mitochondria and myofibrils. In the absence of any anatomical evidence and following the reasoning of Meyer et al.(1984), we do not incorporate compartmentation of ATP and ADP in mitochondrial or myofibrillar pools.