EC Number   |
Reaction |
Reference |
|---|
    4.1.1.22 | L-histidine = histamine + CO2 |
- |
- |
| 4.1.1.22 | L-histidine = histamine + CO2 |
catalytic mechanism, quantum mechanics-molecular mechanics study and molecular dynamics simulations using the enzyme's crystal structure, PDB ID 4E1O, overview. The reaction involves two sequential steps: the decarboxylation of L-histidine and the protonation of the generated intermediate from which results histamine. The rate-limiting step is the first one with an activation barrier of 17.9 kcal/mol. In contrast, the second step is very fast and exergonic. When the substrate L-histidine is available in the active site of HDC, it binds to the pyridoxal 5'-phosphate cofactor. In this process, the imine bond formed between pyridoxal 5'-phosphate and Lys305A is cleaved and a new external aldimine intermediate is created between the pyridoxal 5'-phosphate cofactor and the amino group of the substrate |
747573 |
| 4.1.1.22 | L-histidine = histamine + CO2 |
structure-activity relationship, active site structure, molecular modeling, the imidazole ring is located in a pocket composed of residues Tyr-81B, Asn-302B, Ser-304B, Lys-305B, Leu-102A, Phe-104A, and Ser-354A |
679733 |
