BIOCH 200 Glucose Metabolism (April 4, 2014)
• Why does pyruvate require anaerobic fate?
o So it can be used to produce useful compounds even in the absence of
oxygen. Pyruvate has no useful purpose as is.
Ex. lactate (NOT an acid) via lactate dehydrogenase
• *The “lactic acid” myth
o *Lactic acid is not being produced, only lactate
o *The acidic environment that led to this myth comes
from the release of H+ ions into the muscle cells
caused by the pyruvate to lactate conversion
o *With rest, [lactate] goes down as well as [H+]
because they are symported out thus taking the
acidity with it.
• Causes muscle cramping when muscles partake in
o Leaves muscle tissue by being exported by a specific
membrane transport protein
• *A “dead-end” product that has no useful purpose… in
muscle tissue that is!
o *Lactate can be used as metabolic fuel for cardiac
1) Converted back into pyruvate
• In doing so, reduced NAD+ back into
NADH which can now travel to the ETC
2) Converted to Acetyl-CoA and CO2
• This reduces another NAD+ into NADH
Then it is oxidized by CAC (Citric Acid Cycle)
• Glycolysis Produces: o 2 pyruvate
o 2 NADH
o Net yield of 2 ATP molecules
• *Pyruvate Acetyl CoA (aerobic pathway of pyruvate)
o *Catalyzed by pyruvate dehydrogenase complex (PDH)
• *Oxidative decarboxylation (which is actually just oxidation
• *Transacetylation (transfer of acetyl to Coenzyme A)