AACS ligates CoA-SH to ACA, forming ACA-CoA

Ketone bodies (KBs) are an energy source utilised by mammals, the terminal oxidation of which (termed ketogenesis) is most active during fasting states or starvation. This process normally occurs in the mitochondria of cells. Cytoplasmic de novo lipogenesis and cholesterol synthesis are nonoxidative metabolic fates of ketone bodies. Acetoacetyl-CoA synthetase (AACS) mediates the activation of acetoacetate (ACA) to the KB acetoacetyl-CoA (ACA-CoA) in the cytosol of cells of lipogenic tissues (Aquilo et al. 2010). AACS is proposed to provide an alternative supply of acetyl units from that of mitochondrial ketogenesis for de novo lipogenesis and cholesterol synthesis in the brain, based on rat experiments (Endemann et al. 1982, review Cotter et al. 2013). Human AACS mRNA is abundant in the kidney, heart and brain, but low in liver (Ohgami et al. 2003).

酮体（KBs）是哺乳动物利用的一种能量来源，其终末氧化过程（称为酮生成作用）在禁食状态或饥饿期间最为活跃。此过程通常发生在细胞的线粒体中。酮体的细胞质从头合成脂质和胆固醇是非氧化代谢途径。乙酰乙酰辅酶A合成酶（AACS）介导乙酰乙酸（ACA）在脂生成组织细胞的细胞质中激活为酮体乙酰乙酰辅酶A（ACA-CoA）（Aquilo等，2010年）。基于大鼠实验，AACS被提出为提供一种替代乙酰单元的来源，用于大脑中的从头合成脂质和胆固醇，与线粒体酮生成作用不同（Endemann等，1982年，综述Cotter等，2013年）。人类AACS mRNA在肾脏、心脏和大脑中含量丰富，但在肝脏中含量较低（Ohgami等，2003年）。