OXCT1
OXCT1 (3-oxoacid CoA-transferase 1, also known as SCOT or OXCT) is a mitochondrial enzyme that catalyses the first, rate-limiting step of ketone body utilisation in extrahepatic tissues. It transfers coenzyme A from succinyl-CoA to acetoacetate. Browse Assay Genie's current range of OXCT1 research reagents below, or read on for the biology behind the target.
OXCT1 is a key enzyme of ketone body catabolism. In extrahepatic tissues it catalyses the first, rate-limiting step of ketone body utilisation, transferring coenzyme A (CoA) from a donor thiolester, succinyl-CoA, to an acceptor carboxylate, acetoacetate, to produce acetoacetyl-CoA. Acetoacetyl-CoA is then metabolised by acetoacetyl-CoA thiolase into two molecules of acetyl-CoA, which enter the citric acid cycle for energy production. The reaction is reversible.
The OXCT1 protein is a homodimeric enzyme located in the mitochondrial matrix. Both subunits can form enzyme-CoA thiolester intermediates, but only one subunit is competent to transfer the CoA moiety to the 3-oxo acid acceptor and produce a new acyl-CoA. Formation of the enzyme-CoA intermediate proceeds via an unstable anhydride species formed between the carboxylate groups of the enzyme and the substrate. It belongs to the 3-oxoacid CoA-transferase family.
The OXCT1 gene was previously described as 3-oxoacid CoA transferase or 3-oxoacid CoA transferase 1, and the protein is widely referred to as SCOT (succinyl-CoA:3-ketoacid coenzyme A transferase). Mutations in the gene are associated with succinyl-CoA:3-oxoacid CoA transferase deficiency. Mouse and rat orthologs are both named Oxct1, which supports comparative metabolic studies in rodent models.
OXCT1 catalyses the rate-limiting step of ketone body utilisation in extrahepatic tissues, making it a central enzyme for studying ketolysis.
Its product, acetoacetyl-CoA, is cleaved to acetyl-CoA that enters the citric acid cycle, linking OXCT1 to mitochondrial energy supply.
Mutations in OXCT1 are associated with succinyl-CoA:3-oxoacid CoA transferase deficiency, a focus for genetic and clinical metabolic research.
The dimeric structure, with one subunit competent for CoA transfer via an anhydride intermediate, makes OXCT1 a model for CoA-transferase mechanisms.
OXCT1 transfers coenzyme A from succinyl-CoA to acetoacetate, forming acetoacetyl-CoA. This is the first, rate-limiting step of ketone body utilisation in extrahepatic tissues. Acetoacetyl-CoA is then split into two acetyl-CoA molecules that enter the citric acid cycle.
OXCT1 is also called SCOT and OXCT. The UniProt name is succinyl-CoA:3-ketoacid coenzyme A transferase 1, mitochondrial, and earlier names include 3-oxoacid CoA transferase and 3-oxoacid CoA transferase 1. Its EC number is 2.8.3.5.
Mutations in OXCT1 are associated with succinyl-CoA:3-oxoacid CoA transferase deficiency. Mouse and rat both have an ortholog named Oxct1, but check the datasheet of any product for its validated reactivity.
Other ketone body metabolism enzymes, CoA-transferases and mitochondrial energy metabolism targets with products at Assay Genie.
Gene and protein annotations from HGNC, NCBI Gene and UniProt P55809; product specifications from Assay Genie datasheets.