The link reaction and Krebs cycle

• • pyruvate is converted to acetyl Coenzyme A
  • Acetyl group is oxidised during the Krebs cycle
• pyruvate -> Acetyl Coenzyme A


  2 pyruvate + 2NAD + 2CoA $\rightarrow$ $CO_2$+ 2 reduced NAD + 2 acetyl CoA
• link reaction


  • If oxygen is available the 3C pyruvate created at end of glycolysis passes into the mitochondria
• • The link reaction occurs in the mitochondrial matrix
  • pyruvate is decarboxylated and dehydrogenated, catalysed by pyruvate dehydrogenase which catalyses the sequence of reactions that occur in the link reaction
  • No ATP produced during this reaction
• stages of link reaction

  1. carboxyl group is reduced and is the origin of some of the carbon dioxide produced during respiration
  2. this decarboxylation of pyruvate together with dehydrogenation produces an acetyl group
  3. acetyl group combines with coenzyme A to become acetyl coenzyme A
  4. Coenzyme NAD becomes reduced
• • krebs cycle takes place in the matrix of the mitochondria
  • it is a series of reactions that turn a 6C compound into a 4C compound
• net numbers

  
• krebs cycle and link reaction