Snapshot A 23-year-old man is running a marathon. In the last mile of the race he experiences an intense burning in his muscles. Once he completes the race and rests, the burning slowly subsides. He asks his physician the next day why this may have occurred and what he can do to mitigate it. His physician explains that a training regimen can increase his ability to perform aerobic metabolism, and thus decrease the conversion of pyruvate to lactate (via lactate dehydrogenase) which caused the burning in his muscles that he experienced. Overview Pathways pyruvate → lactate catalyzed by login to view 1 more bullet reversible generated in anaerobic glycolysis login to view 1 more bullet in the liver, LDH converts lactate to pyruvate login to view 3 more bullets pyruvate → acetyl-CoA catalyzed by login to view 1 more bullet irreversible acetyl-CoA enters the citric cycle pyruvate → oxaloacetate catalyzed by login to view 1 more bullet irreversible oxaloacetate can login to view 2 more bullets pyruvate → alanine catalyzed by login to view 1 more bullet reversible alanine carries amino groups to the liver from muscle in the liver, ALT converts alanine to pyruvate login to view 1 more bullet