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EC 4.3.1.23 Details
show Brenda entryEC number
4.3.1.23
Accepted name
tyrosine ammonia-lyase
Reaction
L-tyrosine = trans-p-hydroxycinnamate + NH3
Other name(s)
TAL,
tyrase,
L-tyrosine ammonia-lyase
Systematic name
L-tyrosine ammonia-lyase (trans-p-hydroxycinnamate-forming)
CAS registry number
1030840-68-6
Comment
This enzyme is a member of the aromatic amino acid lyase family, other members of which are EC 4.3.1.3 (histidine 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 [1]. This unique cofactor is formed autocatalytically by cyclization and dehydration of the three amino-acid residues alanine, serine and glycine [3]. The enzyme is far more active with tyrosine than with phenylalanine as substrate, but the substrate specificity can be switched by mutation of a single amino acid (H89F) in the enzyme from the bacterium Rhodobacter sphaeroides [1,2].
History
created 2008 (EC 4.3.1.5 created 1965, part-incorporated 2008)
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1 Oxidoreductases
4 Lyases
4.3.1.8 created 1972, modified 1982, modified 1989, deleted 2003
