ENZYME entry: EC 4.3.1.19

Accepted Name
Threonine ammonia-lyase.
Alternative Name(s)
L-serine dehydratase.
L-threonine deaminase.
L-threonine dehydratase.
L-threonine hydro-lyase (deaminating).
Serine deaminase.
Threonine deaminase.
Threonine dehydrase.
Threonine dehydratase.
Reaction catalysed
L-threonine <=> 2-oxobutanoate + NH(3)
Cofactor(s)
Pyridoxal 5'-phosphate or iron-sulfur.
Comment(s)
  • The reaction catalyzed by both types of enzymes involves the initial elimination of water to form an enamine intermediate (hence the enzyme's original classification as EC 4.2.1.16), followed by tautomerization to an imine form and hydrolysis of the C-N bond.
  • The latter reaction, which can occur spontaneously, is also be catalyzed by EC 3.5.99.10.
  • The enzymes from a number of sources also act on L-serine, cf. EC 4.3.1.17.
  • Formerly EC 4.2.1.16.
Cross-references
PROSITEPDOC00149
BRENDA4.3.1.19
EC2PDB4.3.1.19
ExplorEnz4.3.1.19
PRIAM enzyme-specific profiles4.3.1.19
KEGG Ligand Database for Enzyme Nomenclature4.3.1.19
IUBMB Enzyme Nomenclature4.3.1.19
IntEnz4.3.1.19
MEDLINEFind literature relating to 4.3.1.19
MetaCyc4.3.1.19
UniProtKB/Swiss-Prot
Q9KC63, ILVA_BACHD;  P37946, ILVA_BACSU;  P53607, ILVA_BURM1;  
Q04513, ILVA_CORGL;  P04968, ILVA_ECOLI;  P46493, ILVA_HAEIN;  
Q02145, ILVA_LACLA;  P66898, ILVA_MYCBO;  Q9X7F1, ILVA_MYCLE;  
P9WG94, ILVA_MYCTO;  P9WG95, ILVA_MYCTU;  Q9CKJ2, ILVA_PASMU;  
P20506, ILVA_SALTY;  Q2FF63, ILVA_STAA3;  Q2FWJ9, ILVA_STAA8;  
Q2YUE8, ILVA_STAAB;  Q5HEE0, ILVA_STAAC;  Q99SJ1, ILVA_STAAM;  
Q7A4H2, ILVA_STAAN;  Q3V7T5, ILVA_STAAR;  Q3V7T4, ILVA_STAAS;  
Q8NVI8, ILVA_STAAW;  Q5HMF5, ILVA_STAEQ;  Q8CNK9, ILVA_STAES;  
Q4L7U4, ILVA_STAHJ;  Q49Z16, ILVA_STAS1;  Q0VCW4, SDHL_BOVIN;  
P20132, SDHL_HUMAN;  Q8VBT2, SDHL_MOUSE;  P09367, SDHL_RAT;  
Q96GA7, SDSL_HUMAN;  Q8R238, SDSL_MOUSE;  P25379, STDH_YEAST;  
P0AGF8, TDCB_ECO57;  P0AGF7, TDCB_ECOL6;  P0AGF6, TDCB_ECOLI;  
P11954, TDCB_SALTY;  P0AGF9, TDCB_SHIFL;  Q2FH01, TDCB_STAA3;  
Q2FYJ3, TDCB_STAA8;  Q2YY67, TDCB_STAAB;  Q5HFY5, TDCB_STAAC;  
Q99U50, TDCB_STAAM;  Q7A5L8, TDCB_STAAN;  Q6GGX0, TDCB_STAAR;  
Q6G9C4, TDCB_STAAS;  Q8NWQ4, TDCB_STAAW;  Q9ZSS6, THD1_ARATH;  
Q39469, THD1_CICAR;  P25306, THD1_SOLLC;  P31212, THD1_SOLTU;  
O42615, THDH_BLAAD;  O94634, THDH_SCHPO;  P00927, THDH_YEAST;  
P55664, Y4TJ_RHISN;  

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