acetoacetyl

Acetoacetyl refers to the acetoacetyl group, a four-carbon β-ketoacyl moiety derived from acetoacetic acid (3-oxobutanoic acid). The acetoacetyl group has the structural formula CH3-CO-CH2-CO-, and appears in a range of derivatives including acetoacetyl-CoA, acetoacetyl esters, and diketones.

In metabolism, acetoacetyl-CoA is produced by the thiolase-catalyzed condensation of two acetyl-CoA molecules. This intermediate feeds several pathways: it can be converted to HMG-CoA, a precursor in cholesterol and isoprenoid biosynthesis, or coupled with CoA to form acetyl-CoA for energy production through ketone body metabolism, especially during fasting or carbohydrate restriction.

Protein and histone modifications: Acetoacetyl groups can be transferred to proteins in a process called acetoacetylation, using acetoacetyl-CoA as the donor. This post-translational modification links cellular metabolism to regulation of gene expression and chromatin structure, and is an area of active research.

In synthetic chemistry, the acetoacetyl group is a common building block for beta-keto esters and related compounds. It participates in various condensation and functional-group interconversion reactions, including enolate chemistry and Claisen-type condensations.