The link reaction

The link reaction

1. Converts pyruvate (from glycolysis) to acetate. NAD is reduced.

   • Decarboxylation and dehydrogenation are enzyme catalysed reactions (pyruvate is substrate)
     • Pyruvate dehydrogenase removes H atoms; pyruvate decarboxylase removes a carboxyl group
     • Coenzyme NAD accepts the H atoms; coenzyme A (CoA) accepts the acetate > acetyl CoA

2. Takes place in the matrix, so pyruvate has to be transported into mitochondria from the cytoplasm

3. 2 pyruvate + 2 NAD+ (oxidised) + 2 CoA ------> 2 CO2 + 2 reduced NAD + 2 acetyl CoA

   • No ATP produced, but each NADH carrying 2 H atoms - will take to inner mitochondrial membrane where H atoms used to produce ATP during oxidative phosphorylation
   • 2 molecules of everything because two molecules of pyruvate derived from each glucose molecule

4. Pyruvate is 3C, acetate is 2C, acetyl CoA is 2C

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