Cori cycle

From Wikipedia, the free encyclopedia

The Cori cycle refers to the cycling of lactate or lactic acid produced by red blood cells and muscle (during anaerobic respiration) back into glucose.

[edit] The cycle

When muscles require energy for short duration, strenuous movements, muscle cells default to anaerobic glycolysis to quickly produce abundant amounts of ATP. The byproduct of anaerobic gycolysis, lactic acid, diffuses into the blood and is taken up by the liver, where it is converted back into pyruvate by the enzyme lactate dehydrogenase. Pyruvate is then converted back into glucose via gluconeogenesis. The newly formed glucose is released into the blood to be used once again for energy by the red blood cells and muscle. Note that the Cori cycle is energy consuming(6 ATP used per glucose molecule made).

[edit] Significant

It's importance is based on the prevention of lactic acidosis in the muscle under anarobic condition. The muscles are clamped when the lactate is accumulated. Lactate is the blind end of the biochemical reaction. The unwanted lactate can be only converted to pyruvate with lactate dehydrogenase.

For red blood cells (erythrocytes), the cycle is essential as the cells don't contain the mitochrondria; the significant is to preserve the oxygen transported by the cells. The NAD⁺ can be regenerated via the lactate fermentation. The Cori cycle is essential for maintaining glycolysis in the erythrocytes as the Cori cycle continue providing the glucose molecules as the fuel molecules.