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

Calculations of fractional H+ exchange (~H+e) from the chemical reactions of non ‐mitochondrial energy catabolism were performed to quantify the extent of ~H+ release during 3  min of intense muscle contractions. The total ~H+ release was −187.9 mmol L−1 and total ~H+ consumption was 130.6  mmol L−1. The largest sources of ~H+ release were from glycolysis and ATP hydrolysis and the largest contributor to ~H+ consumption was lactate production (44.2  mmol L−1). AbstractThe purpose of this investigation was to present calculations of fractional H+ exchange (~H+e) 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+e from specific chemical reactions. Data revealed that the 3  min of intense exercise incurred a total ATP turnover of 142.5 mmol L−1, with a total intramuscular ~H+ exchange ( ‐‘ve = release) of −187.9 mmol L−1. Total ~H+ metabolic consumption was 130.6  mmol L−1, revealing a net total ~H+e (~H+te) of −57.3 mmol L−1. Lactate production had a ~H+te of 44.2  mmol L−1 (for a peak accumulation  = 45 mmo...
Source: Physiological Reports - Category: Physiology Authors: Tags: ORIGINAL RESEARCH Source Type: research