In humans, dihydrolipoyl transacetylase enzymatic activity resides in the pyruvate dehydrogenase complex component E2 (PDCE2) that is encoded by the DLAT (dihydrolipoamide S-acetyltransferase) gene.

The two main substrates, CoA and the lipoamide (Lip(SH)2), are found at two opposite entrances of a 30 Å long channel which runs between the subunits and forms the catalytic center.

[10] In many species, including bacteria such as Geobacillus stearothermophilus and Enterococcus faecalis [7] as well as mammals such as humans[11] and cows,[12] the dodecahedral core structure is made up of 60 subunits total.

These metabolic processes are important for cellular respiration—the conversion of biochemical energy from nutrients into adenosine triphosphate (ATP) which can then be used to carry out numerous biological reactions within a cell.

Thus pyruvate dehydrogenase complexes (containing the dihydrolipoyl transacetylase enzymes) are found in the mitochondria of eukaryotes (and simply in the cytosol of prokaryotes).

The dihydrolipoamide is taken up by dihydrolipoyl dehydrogenase, and with the additional cofactors FAD and NAD+, regenerates the original lipoamide (with NADH as a useful side product).

[13] Recent evidence has suggested that peptides within the catalytic site may present the immunodominant epitopes recognized by the anti-PDC-E2 antibodies in PBC patients.

[15] Pyruvate dehydrogenase deficiency (PDH) is a genetic disease resulting in lactic acidosis as well as neurological dysfunction in infancy and early childhood.