0-Keto Acyl CoA

The reaction occurs by nucleophilic addition of coenzyme A to the keto group of the 0-keto acyl CoA to yield an alkoxide ion intermediate, followed by cleavage of the C2-C3 bond with expulsion of an acetyl CoA enolate ion. Protonation of the enolate ion gives acetyl CoA, and the chain-shortened acyl CoA enters another round of the 0-oxidation pathway for further degradation. 

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