L-threonine 3-dehydrogenase

Class of enzymes

L-threonine 3-dehydrogenase homotetramer, Thermus thermophilus

Identifiers

EC no.

1.1.1.103

CAS no.

9067-99-6

Databases

IntEnz

IntEnz view

BRENDA

BRENDA entry

ExPASy

NiceZyme view

KEGG

KEGG entry

MetaCyc

metabolic pathway

PRIAM

profile

PDB structures

RCSB PDB PDBe PDBsum

Gene Ontology

AmiGO / QuickGO

Search
PMC	articles
PubMed	articles
NCBI	proteins

L-Threonine dehydrogenase

Identifiers

Symbol

TDH

NCBI gene

157739

HGNC

15547

RefSeq

NM_152566

UniProt

Q8IZJ6

Other data

EC number

1.1.1.103

Locus

Chr. 8 p23.1

Search for
Structures	Swiss-model
Domains	InterPro

In enzymology, a L-threonine 3-dehydrogenase (EC 1.1.1.103) is an enzyme that catalyzes the chemical reaction

L-threonine + NAD⁺

\rightleftharpoons

L-2-amino-3-oxobutanoate + NADH + H⁺

Thus, the two substrates of this enzyme are L-threonine and NAD⁺, whereas its 3 products are L-2-amino-3-oxobutanoate, NADH, and H⁺.

This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD⁺ or NADP⁺ as acceptor. The systematic name of this enzyme class is L-threonine:NAD⁺ oxidoreductase. Other names in common use include L-threonine dehydrogenase, threonine 3-dehydrogenase, and threonine dehydrogenase. This enzyme participates in glycine, serine and threonine metabolism.

Structural studies

As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes 2D8A, 2DFV, and 2DQ4.

References

Green ML, Elliott WH (1964). "The enzymic formation of aminoacetone from threonine and its further metabolism". Biochem. J. 92 (3): 537–49. doi:10.1042/bj0920537. PMC 1206098. PMID 4284408.
Hartshorne D, Greenberg DM (1964). "Studies on liver threonine dehydrogenase". Arch. Biochem. Biophys. 105: 173–8. doi:10.1016/0003-9861(64)90250-4. PMID 14165492.
Epperly BR, Dekker EE (April 1991). "L-threonine dehydrogenase from Escherichia coli. Identification of an active site cysteine residue and metal ion studies". The Journal of Biological Chemistry. 266 (10): 6086–92. doi:10.1016/S0021-9258(18)38087-6. PMID 2007567.
Edgar AJ (October 2002). "The human L-threonine 3-dehydrogenase gene is an expressed pseudogene". BMC Genetics. 3: 18. doi:10.1186/1471-2156-3-18. PMC 131051. PMID 12361482.

Metabolism: Protein metabolism, synthesis and catabolism enzymes

Essential amino acids are in Capitals

K→acetyl-CoA

LYSINE→	Saccharopine dehydrogenase Glutaryl-CoA dehydrogenase
LEUCINE→	3-Hydroxybutyryl-CoA dehydrogenase Branched-chain amino acid aminotransferase Branched-chain alpha-keto acid dehydrogenase complex Enoyl-CoA hydratase HMG-CoA lyase HMG-CoA reductase Isovaleryl coenzyme A dehydrogenase α-Ketoisocaproate dioxygenase Leucine 2,3-aminomutase Methylcrotonyl-CoA carboxylase Methylglutaconyl-CoA hydratase (See Template:Leucine metabolism in humans – this diagram does not include the pathway for β-leucine synthesis via leucine 2,3-aminomutase)
TRYPTOPHAN→	Indoleamine 2,3-dioxygenase/Tryptophan 2,3-dioxygenase Arylformamidase Kynureninase 3-hydroxyanthranilate oxidase Aminocarboxymuconate-semialdehyde decarboxylase Aminomuconate-semialdehyde dehydrogenase
PHENYLALANINE→tyrosine→	(see below)

G→pyruvate
→citrate

glycine→serine→	Serine hydroxymethyltransferase Serine dehydratase glycine→creatine: Guanidinoacetate N-methyltransferase Creatine kinase
alanine→	Alanine transaminase
cysteine→	D-cysteine desulfhydrase
threonine→	L-threonine dehydrogenase

G→glutamate→
α-ketoglutarate

HISTIDINE→	Histidine ammonia-lyase Urocanate hydratase Formiminotransferase cyclodeaminase
proline→	Proline oxidase Pyrroline-5-carboxylate reductase 1-Pyrroline-5-carboxylate dehydrogenase/ALDH4A1 PYCR1
arginine→	Ornithine aminotransferase Ornithine decarboxylase Agmatinase
→alpha-ketoglutarate→TCA	Glutamate dehydrogenase
Other	cysteine+glutamate→glutathione: Gamma-glutamylcysteine synthetase Glutathione synthetase Gamma-glutamyl transpeptidase glutamate→glutamine: Glutamine synthetase Glutaminase

G→propionyl-CoA→
succinyl-CoA

VALINE→	Branched-chain amino acid aminotransferase Branched-chain alpha-keto acid dehydrogenase complex Enoyl-CoA hydratase 3-hydroxyisobutyryl-CoA hydrolase 3-hydroxyisobutyrate dehydrogenase Methylmalonate semialdehyde dehydrogenase
ISOLEUCINE→	Branched-chain amino acid aminotransferase Branched-chain alpha-keto acid dehydrogenase complex 3-hydroxy-2-methylbutyryl-CoA dehydrogenase
METHIONINE→	generation of homocysteine: Methionine adenosyltransferase Adenosylhomocysteinase regeneration of methionine: Methionine synthase/Homocysteine methyltransferase Betaine-homocysteine methyltransferase conversion to cysteine: Cystathionine beta synthase Cystathionine gamma-lyase
THREONINE→	Threonine aldolase
→succinyl-CoA→TCA	Propionyl-CoA carboxylase Methylmalonyl CoA epimerase Methylmalonyl-CoA mutase

G→fumarate

PHENYLALANINE→tyrosine→	Phenylalanine hydroxylase Tyrosine aminotransferase 4-Hydroxyphenylpyruvate dioxygenase Homogentisate 1,2-dioxygenase Fumarylacetoacetate hydrolase tyrosine→melanin: Tyrosinase

G→oxaloacetate

asparagine→aspartate→	Asparaginase/Asparagine synthetase Aspartate transaminase

v t e Oxidoreductases: alcohol oxidoreductases (EC 1.1)
1.1.1: NAD/NADP acceptor	3-hydroxyacyl-CoA dehydrogenase 3-hydroxybutyryl-CoA dehydrogenase Alcohol dehydrogenase Aldo-keto reductase 1A1 1B1 1B10 1C1 1C3 1C4 7A2 Aldose reductase Beta-Ketoacyl ACP reductase Carbohydrate dehydrogenases Carnitine dehydrogenase D-malate dehydrogenase (decarboxylating) DXP reductoisomerase Glucose-6-phosphate dehydrogenase Glycerol-3-phosphate dehydrogenase HMG-CoA reductase IMP dehydrogenase Isocitrate dehydrogenase Lactate dehydrogenase L-threonine dehydrogenase L-xylulose reductase Malate dehydrogenase Malate dehydrogenase (decarboxylating) Malate dehydrogenase (NADP+) Malate dehydrogenase (oxaloacetate-decarboxylating) Malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+) Phosphogluconate dehydrogenase Sorbitol dehydrogenase Hydroxysteroid dehydrogenase: 3β 3β-HSD NSDHL 11β 11β-HSD1 11β-HSD2 17β
1.1.2: cytochrome acceptor	D-lactate dehydrogenase (cytochrome) D-lactate dehydrogenase (cytochrome c-553) Mannitol dehydrogenase (cytochrome)
1.1.3: oxygen acceptor	Glucose oxidase L-gulonolactone oxidase Xanthine oxidase Alcohol oxidase
1.1.4: disulfide as acceptor	Vitamin K epoxide reductase Vitamin-K-epoxide reductase (warfarin-insensitive)
1.1.5: quinone/similar acceptor	Malate dehydrogenase (quinone) Quinoprotein glucose dehydrogenase
1.1.99: other acceptors	Choline dehydrogenase L2HGDH

v t e Enzymes
Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Diffusion-limited enzyme Cofactor Enzyme catalysis
Regulation	Allosteric regulation Cooperativity Enzyme inhibitor Enzyme activator
Classification	EC number Enzyme superfamily Enzyme family List of enzymes
Kinetics	Enzyme kinetics Eadie–Hofstee diagram Hanes–Woolf plot Lineweaver–Burk plot Michaelis–Menten kinetics
Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list) EC7 Translocases (list)