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Literature summary for 4.1.1.22 extracted from

  • Fernandes, H.S.; Ramos, M.J.; Cerqueira, N.M.F.S.A.
    The catalytic mechanism of the pyridoxal-5'-phosphate-dependent enzyme, histidine decarboxylase a computational study (2017), Chemistry, 23, 9162-9173 .
    View publication on PubMed
Search for more literature for 4.1.1.22

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
0.1
-
 L-histidine pH and temperature not specified in the publication Homo sapiens

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
L-histidine Homo sapiens
-
 histamine + CO2
-
 ?

Organism

Organism UniProt Comment Textmining
Homo sapiens P19113
-
-

Reaction

Reaction Comment Organism Reaction ID
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 Homo sapiens
a

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
L-histidine
-
 Homo sapiens histamine + CO2
-
 ?

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
1.73
-
 L-histidine pH and temperature not specified in the publication Homo sapiens

Cofactor

Cofactor Comment Organism Structure
pyridoxal 5'-phosphate
-
 Homo sapiens

General Information

General Information Comment Organism
evolution the enzyme belongs to the family of pyridoxal 5'-phosphate-dependent decarboxylases Homo sapiens
additional information active site residues of the dimeric enzyme are Tyr334B, Asp273A, Lys305A, and Ser354B, which are involved in catalysis Homo sapiens

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
17.3
-
 L-histidine pH and temperature not specified in the publication Homo sapiens