Quantifying H exchange from muscle cytosolic energy catabolism using metabolite flux and H coefficients from multiple competitive cation binding: New evidence for consideration in established theories.

The purpose of this investigation was to present calculations of fractional H exchange (H ) from the chemical reactions of non-mitochondrial energy catabolism. Data of muscle pH and metabolite accumulation were based on published research for intense exercise to contractile failure within ~3 min, from which capacities and time profiles were modeled. Data were obtained from prior research for multiple competitive cation dissociation constants of metabolites and the chemical reactions of non-mitochondrial energy catabolism, and pH dependent calculations of ~H from specific chemical reactions. Data revealed that the 3 min of intense exercise incurred a total ATP turnover of 142.5 mmol L , with a total intramuscular ~H exchange (-'ve = release) of -187.9 mmol L . Total ~H metabolic consumption was 130.6 mmol L , revealing a net total ~H (H ) of -57.3 mmol L . Lactate production had a ~H of 44.2 mmol L (for a peak accumulation = 45 mmol L ). The net ~H for the sum of the CK, AK, and AMPD reactions was 36.33 mmol L . The ~H from ATP turnover equaled -47.5 mmol L . The total ~H release to lactate ratio was 4.3 (187.9/44). Muscle ~H release during intense exercise is up to ~4-fold larger than previously assumed based on the lactic acid construct.