This gene encodes a homotetrameric mitochondrial flavoprotein and is a member of the acyl-CoA dehydrogenase family. Members of this family catalyze the first step of fatty acid beta-oxidation, forming a C2-C3 trans-double bond in a FAD-dependent reaction. As beta-oxidation cycles through its four steps, each member of the Acyl-CoA dehydrogenase family works at an optimum fatty acid chain-length. This enzyme has its optimum at C(four)-CoA. In mice, deficiency of this gene has been linked to cold sensitivity and increased high-density lipoprotein levels. [provided by RefSeq, Nov 2012]