ACSF1 is a 672 amino acid protein belonging to the ATP-dependent AMP-binding enzyme family. Encoded by a gene that maps to human chromosome 12q24.31, ACSF1 is highly expressed in kidney, heart and brain, and shows similar neural expression as HMGCR (3-hydroxy-3-methylglutaryl-CoA reductase). Existing as three alternatively spliced isoforms, ACSF1 participates in ATP binding, ligase activity, acetoacetate-CoA ligase activity and nucleotide binding. The ACSF1 promoter is a known PPAR?target gene, with the nuclear receptor recruited to the ACSF1 promoter by direct interaction with stimulating protein-1 (Sp1). ACSF1 activates acetoacetate and is highly regulated by modulators that affect HMGCR and cholesterol biosynthesis.