The enzyme catalyzes the decarboxylation of a branched-chain 2-oxo acid concomitant with the formation of the alpha-carbanion/enamine intermediate, 2-(1-hydroxyalkyl)-ThDP, followed by transfer of the 1-hydroxyalkyl group to the distal sulfur atom on the lipoamide of the E2 component (PMID15033367).
CATALYTIC METAL(S)
| Metal/Site Information | |||||
| Residue in MACiE* | Atom in MACiE* | Residue Type in MACiE | Physiological Metal |
Site Type |
Function(s) |
| MG 401 A | MG | magnesium | magnesium | mononuclear | Coordinates substrate |
| K 402 A | K | potassium | potassium | mononuclear | Structural |
| K 343 B | K | potassium | potassium | mononuclear | Structural |
*It refers to the MACiE reference pdb: 1dtw
| Metal/s Properties in Resting State | ||||||
| MG 401 A | Resting state enzyme (-) | |||||
| Oxidation State | 2 | |||||
| Coordination Geometry | unknownGeometry | |||||
| Coordination Number | unknown | |||||
| Notes | - | |||||
| K 402 A | Resting state enzyme (-) | |||||
| Oxidation State | 1 | |||||
| Coordination Geometry | unknownGeometry | |||||
| Coordination Number | unknown | |||||
| Notes | - | |||||
| K 343 B | Resting state enzyme (-) | |||||
| Oxidation State | 1 | |||||
| Coordination Geometry | unknownGeometry | |||||
| Coordination Number | unknown | |||||
| Notes | - | |||||
| References |
| -Machius M, Chuang JL, Li J, Tomchick DR, Chuang DT Roles of His291-alpha and His146-beta' in the reductive acylation reaction catalyzed by human branched-chain alpha-ketoacid dehydrogenase: refined phosphorylation loop structure in the active site. J Biol Chem. 2003 Oct 31;278(44):43402-10. Epub 2003 Aug 5.(MEDLINE:12902323) |
| -Chuang JL, Wynn RM, Turley S, Chuang DT, Hol WG Crystal structure of human branched-chain alpha-ketoacid dehydrogenase and the molecular basis of multienzyme complex deficiency in maple syrup urine disease. Structure. 2000 Mar 15;8(3):277-91.(MEDLINE:10745006) |