Study GuideBiochemistry-II–Integrated Metabolism1.Exercise and MetabolismExercise and fasting place special demands on the body’s metabolism. The type of activity—short andintense or long and sustained—determineswhich energy systems are usedandhow nucleotideslike ATP are regenerated.1.1Immediate Energy for Exercise: Creatine PhosphateRole of Creatine PhosphateSprinting requires avery rapid supply of energy. The first energy source used by muscles iscreatine phosphate (Cr~P).•Creatine contains aguanidino group, similar to arginine•It acts as astorage system for high-energy phosphate bondsin muscle•The free energy of hydrolysis of creatine phosphate is about10.3 kcal/mol, which ishigherthan ATPThis makes creatine phosphate an excellenttemporary energy reservoir.Creatine Kinase ReactionCreatine phosphate transfers its phosphate group to ADP to regenerate ATP.Although this reaction favors the left side under standard conditions,real muscle cells are not instandard conditions.•ATP : ADP ratio in active muscle can be50–100 : 1•This drives the formation and use of creatine phosphate•Creatine phosphate functions like acharged battery or water reservoir, storing energy forrapid releasePreview Mode
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