| Property | Summary |
|---|---|
| Gene name | **DBT**; synonyms include **BCATE2** and **BCKDHE2** (UniProt P11182 context from prompt; function/disease literature confirms DBT as the E2 subunit of BCKDH) (pqac-00000000, pqac-00000001) |
| Protein name | **Dihydrolipoamide branched-chain transacylase E2**; also called **branched-chain 2-oxo acid dehydrogenase complex component E2 / BCKDH-E2 / BCOADC-E2** (pqac-00000000, pqac-00000001, pqac-00000011) |
| UniProt ID | **P11182** (user-provided target identification) |
| EC number | **EC 2.3.1.168** (user-provided target identification; consistent with acyltransferase role summarized in literature) (pqac-00000000, pqac-00000001) |
| Organism | **Homo sapiens (human)** (user-provided target identification; human disease literature on MSUD and PBC pertains to this ortholog) (pqac-00000023, pqac-00000029) |
| Chromosomal location | **Chromosome 1p31** (standard human gene annotation; not directly documented in the retrieved context set, so best treated as canonical database annotation rather than literature-derived) |
| Protein size | **Mitochondrial precursor protein; historically described as a ~52 kDa mitochondrial autoantigen in PBC** (exact residue length not established from retrieved contexts) (pqac-00000001, pqac-00000011) |
| Subcellular localization | **Mitochondrial matrix / inner-mitochondrial multienzyme complex** involved in branched-chain amino acid oxidation (pqac-00000003, pqac-00000049) |
| Enzyme complex | Core **E2 transacylase** component of the **branched-chain α-ketoacid dehydrogenase (BCKDH/BCKDC) complex**, together with E1α/E1β and E3 subunits (pqac-00000000, pqac-00000001, pqac-00000029) |
| Domain structure | E2 contains an **N-terminal lipoyl-bearing domain**, an **E1/E3-binding (subunit-binding) domain**, and a **C-terminal inner-core/catalytic domain**, linked by flexible regions (pqac-00000003, pqac-00000002) |
| Catalytic function | **Acyltransferase/transacylase** that accepts the oxidized branched-chain acyl intermediate from E1 on its lipoyl arm and transfers the acyl group to **CoA**, yielding branched-chain acyl-CoA products (pqac-00000000, pqac-00000001) |
| Substrates | Indirectly acts on the branched-chain α-ketoacids produced from BCAAs: **KIC** (from leucine), **KMV** (from isoleucine), and **KIV** (from valine), via transfer of their decarboxylated acyl groups to CoA (pqac-00000001, pqac-00000000) |
| Products | Corresponding **branched-chain acyl-CoA conjugates** plus reduced/reoxidized lipoyl intermediates as part of the overall oxidative decarboxylation cycle (pqac-00000000, pqac-00000001) |
| Cofactor | **Covalently attached lipoic acid (lipoyl-lysine arm)**, which acts as a flexible swinging arm between active sites and is essential for catalysis (pqac-00000000, pqac-00000002, pqac-00000033) |
| Complex assembly | DBT forms the **24-subunit E2 structural core** of BCKDH, serving as the scaffold for assembly of E1 and E3 components (pqac-00000003, pqac-00000001) |
| Regulatory interactions | **BDK/BCKDK** binds the E2 core/lipoyl-binding interface to phosphorylate and inhibit E1α; **PPM1K/PP2Cm** counteracts this by dephosphorylating E1α and reactivating the complex. E2/DBT is therefore central to regulatory docking and complex control (pqac-00000004, pqac-00000009, pqac-00000035, pqac-00000037) |
| Disease associations | **MSUD type II (E2 deficiency)** from biallelic DBT defects; **primary biliary cholangitis/cirrhosis autoantigen** (BCOADC-E2); **cuproptosis-related lipoylated mitochondrial protein**; also implicated in **RNS-mediated metabolic inhibition** and cancer biomarker studies (pqac-00000023, pqac-00000011, pqac-00000022, pqac-00000030) |
| Key pathways | **Branched-chain amino acid catabolism** and broader **mitochondrial oxidative metabolism**; pathway intersects with lipid metabolism, insulin resistance biology, and mitochondrial stress/cell death signaling (pqac-00000004, pqac-00000005, pqac-00000021) |


*Table: This table summarizes the core molecular, enzymatic, structural, and disease-related properties of human DBT/BCKDH-E2. It is useful as a compact reference for functional annotation and for linking DBT’s biochemical role to MSUD, autoimmunity, and recent mitochondrial stress research.*