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Information on EC 4.3.1.3 - histidine ammonia-lyase

for references in articles please use BRENDA:EC4.3.1.3

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IUBMB Comments

This enzyme is a member of the aromatic amino acid lyase family, other members of which are EC 4.3.1.23 (tyrosine ammonia-lyase), EC 4.3.1.24 (phenylalanine ammonia-lyase) and EC 4.3.1.25 (phenylalanine/tyrosine ammonia-lyase). The enzyme contains the cofactor 3,5-dihydro-5-methylidene-4H-imidazol-4-one (MIO), which is common to this family . This unique cofactor is formed autocatalytically by cyclization and dehydration of the three amino-acid residues alanine, serine and glycine . This enzyme catalyses the first step in the degradation of histidine and the product, urocanic acid, is further metabolized to glutamate [2,3].

The enzyme appears in viruses and cellular organisms
Reaction Schemes

Synonyms
hal, histidase, histidine ammonia-lyase, histidine ammonia lyase, histidinase, l-histidase, more

REACTION
REACTION DIAGRAM
COMMENTARY hide
ORGANISM
UNIPROT
LITERATURE
L-histidine = urocanate + NH3
show the reaction diagram
PATHWAY SOURCE
PATHWAYS
MetaCyc
L-histidine degradation I, L-histidine degradation II, L-histidine degradation III, L-histidine degradation VI