ACADS is a tetrameric mitochondrial flavoprotein, which is a member of the acyl-CoA dehydrogenase family.  ACADS plays a vital role in the mitochondrial fatty acid beta-oxidation pathway by catalyzing the rate-limiting step. This process is essential for the breakdown of fatty acids, which provides energy for cellular functions, particularly during periods of fasting or prolonged exercise. Deficiencies in ACADS can lead to serious metabolic disorders, such as short-chain acyl-CoA dehydrogenase deficiency, characterized by the accumulation of butyrylcarnitine and ethylmalonic acid, resulting in acute acidosis and muscle weakness in infants, as well as lipid-storage myopathy in adults. The presence of four FAD domains within the ACADS structure is significant, as these domains are critical for the enzyme′s activity and stability, underscoring the importance of this protein in maintaining metabolic homeostasis.