- Certain intermediates of the TCA Cycle can be removed to serve as precursors for many reactions needed by the body. Example-
- Heme is synthesized from Succinyl CoA
- Aspartate is synthesised from Oxaloacetate
- This causes TCA cycle to slow down
- To counterbalance such loses, and to keep the concentrations of the 4-carbon units in the cell, the intermediates must be replenished through other enzymatic reactions.
- Such reactions are known as Anaplerotic Reactions or Filling Up Reactions or Influx reactions or replenishing reactions,
- Important anaplerotic reactions are-
- Pyruvate to OAA by pyruvate carboxylase and ATP.
- Transamination reactions-
- Glutamate to Alpha keto glutarate
- Aspartate to OAA(oxaloacetate)
- Carboxylation of Pyruvate to malate by NADP dependent malic enzyme Malate dehydrogenase.