HADHB encodes a 51.2 kDa protein that is composed of 474 amino acids; 124 peptides have been observed through mass spectrometry data.

The HADHB protein catalyzes the final step of beta-oxidation, in which 3-ketoacyl CoA is cleaved by the thiol group of another molecule of Coenzyme A.

The genes of the alpha and beta subunits of the mitochondrial trifunctional protein are located adjacent to each other in the human genome in a head-to-head orientation.

[10] Additionally, some presents showed symptoms associated with myopathy, recurrent and episodic rhabdomyolysis, and sensorimotor axonal neuropathy.

[13] HADHB is a functional molecular target of ERα in the mitochondria, and the interaction may play an important role in the estrogen-mediated lipid metabolism in animals and humans.