HAL

Histidine ammonia-lyase is a cytosolic enzyme catalyzing the first reaction in histidine catabolism, the nonoxidative deamination of L-histidine to trans-urocanic acid. Histidine ammonia-lyase defects cause histidinemia which is characterized by increased histidine and histamine and decreased urocanic acid in body fluids. Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Apr 2012]

Histidine Ammonia-Lyase

Histidine catabolic process Source: GO_Central
Histidine catabolic process to glutamate and formamide Source: UniProtKB-UniPathway
Histidine catabolic process to glutamate and formate Source: UniProtKB-UniPathway

Cytosol

Histidinemia (HISTID):
Autosomal recessive disease characterized by increased histidine and histamine as well as decreased urocanic acid in body fluids.

Contains an active site 4-methylidene-imidazol-5-one (MIO), which is formed autocatalytically by cyclization and dehydration of residues Ala-Ser-Gly.