pyruvate carboxylase deficiency is an inherited metabolic disorder where anaplerosis is greatly reduced. Other anaplerortic substrates such as the odd-carbon containing triglyceride Triheptanoin is used to treat this disorder.
There are 4 reactions classed as anaplerotic, yet the production of oxaloacetate from pyruvate has probably the most physiologic importance.
|Pyruvate||oxaloacetate||pyruvate + CO2 + H2O + ATP oxaloacetate + ADP + Pi + 2H+||This reaction is catalysed by pyruvate carboxylase, an enzyme activated by Acetyl-CoA, indicating a lack of oxaloacetate. Pyruvate can also be converted to L-malate, another intermediate, in a similar way.|
|Aspartate||oxaloacetate||-||This is a reversible reaction forming oxaloacetate from aspartate in a transamination reaction, via aspartate transaminase.|
|Glutamate||α-ketoglutarate||glutamate + NAD+ + H2O NH4+ + α-ketoglutarate + NADH + H+.||This reaction is catalysed by glutamate-dehydrogenase.|
|β-oxidation of fatty acids||succinyl-CoA||-||When odd-chain fatty acids are oxidized, one molecule of succinyl-CoA is formed per fatty acid. The final enzyme is methylmalonyl-CoA mutase.|