Succinyl-CoA

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CASNo = 604-98-8
PubChem = 1111
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MeSHName = succinyl-coenzyme+A
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Formula = C₂₅H₄₀N₇O₁₉P₃S
MolarMass = 867.608
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Succinyl-Coenzyme A, generally abbreviated as Succinyl-CoA or SucCoA is a combination of succinic acid and coenzyme A.

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It is an important intermediate in the citric acid cycle, where it is synthesized from α-Ketoglutarate by α-ketoglutarate dehydrogenase through decarboxylation. During the process, coenzyme A is added.

It is also synthesized from propionyl CoA, the odd numbered fatty acid which cannot undergo beta-oxidation. [cite journal |author=Halarnkar PP, Blomquist GJ |title=Comparative aspects of propionate metabolism |journal=Comp. Biochem. Physiol., B |volume=92 |issue=2 |pages=227–31 |year=1989 |pmid=2647392] Propionyl-CoA is carboxylated to D-methylmalonyl-CoA, isomerized to L-methylmalonyl-CoA, and rearranged to yield succinyl-CoA via a vitamin B12-dependent enzyme. Succinyl-CoA is an intermediate of the citric acid cycle and can be readily incorporated there.

Fate

It is converted into succinate through the hydrolytic release of coenzyme A by succinyl-CoA synthetase (succinate thiokinase).

Another fate of succinyl-CoA is porphyrin synthesis, where succinyl-CoA and glycine are combined by ALA synthase to form δ-aminolevulinic acid (dALA).

Formation

Succinyl CoA can be formed from methylmalonyl CoA through the utilization of deoxyadenosyl-B12 (deoxyadenosylcobalamin) by methylmalonyl CoA Mutase. This reaction, which requires vitamin B12 to occur, is important in the catabolism of some branched-chain amino acids as well as odd-chain fatty acids.

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