succinyl coenzyme A

Function

• succinyl CoA is an intermediate in the citric acid cycle.
• it is formed from alpha-ketoglutarate via alpha-ketoglutarate dehydrogenase in a reaction that feeds electrons into the electron transport chain via NADH
  • enzyme: alpha-ketoglutarate dehydrogenase
  • substrates: alpha-ketoglutarate + NAD+ + coenzyme-A
  • products: succinyl-CoA + CO2 + NADH
• it is hydrolyzed to form succinate by succinyl CoA synthase
  • enzyme: succinyl-CoA synthetase
  • substrates: succinyl-CoA + GDP + H2PO4-
  • products: succinate + coenzyme-A + GTP
• succinyl CoA also serves as a port of entry into the citric acid cycle, from methylmalonyl CoA in a vitamin B12-dependent reaction catalyzed by methylmalonyl CoA mutase.

* see citric acid cycle for role of succinyl CoA in citric acid cycle

• succinyl CoA serves as an intermediate in the catabolism of odd chain fatty acids, cholesterol & the amino acids methionine, valine & isoleucine
• succinyl CoA & glycine condense to form delta-aminolevulinate in the first step of the biosynthesis of heme in a reaction catalyzed by delta-aminolevulinate synthase within mitochondria.

More general terms

• succinate; succinic acid
• acyl Coenzyme A
• intermediary metabolite

Additional terms

• citric acid cycle, Krebs cycle or tricarboxylic acid [TCA] cycle
• heme synthesis

Database

• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=1111
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=439161
• PubChem: http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=5313