Biology:L-threonine 3-dehydrogenase
| L-threonine 3-dehydrogenase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
 L-threonine 3-dehydrogenase homotetramer, Thermus thermophilus | |||||||||
| Identifiers | |||||||||
| EC number | 1.1.1.103 | ||||||||
| CAS number | 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 | ||||||||
| |||||||||
In enzymology, L-threonine 3-dehydrogenase (EC 1.1.1.103), or just threonine dehydrogenase, is an enzyme that participates in the process of breaking down threonine in certain non-human organisms like mice.[1] In particular, it catalyzes the chemical reaction
- REDIRECT Template:Chemical reaction
The two substrates of this enzyme are L-threonine and oxidised nicotinamide adenine dinucleotide (NAD+). Its products are (S)-2-amino-3-ketobutyric acid, reduced NADH, and a proton.[2][3][4][5][6]
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, and threonine 3-dehydrogenase.
In humans
In humans, the homolog gene, TDH, is a non-functional pseudogene.[7] The loss of an acceptor splice site consistently leads to a non-functional truncated protein.[7] The primary pathway for threonine degradation in humans instead starts with threonine ammonia-lyase (aka threonine dehydratase) and produces propionyl-CoA instead of glycine.[8]
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
- ↑ "Q8K3F7 · TDH_MOUSE". UniProt consortium. https://www.uniprot.org/uniprotkb/Q8K3F7/entry.
- ↑ Enzyme 1.1.1.103 at KEGG Pathway Database.
- ↑ "The enzymic formation of aminoacetone from threonine and its further metabolism". Biochem. J. 92 (3): 537–49. 1964. doi:10.1042/bj0920537. PMID 4284408.
- ↑ "Studies on liver threonine dehydrogenase". Arch. Biochem. Biophys. 105: 173–8. 1964. doi:10.1016/0003-9861(64)90250-4. PMID 14165492.
- ↑ "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. April 1991. doi:10.1016/S0021-9258(18)38087-6. PMID 2007567.
- ↑ "The human L-threonine 3-dehydrogenase gene is an expressed pseudogene". BMC Genetics 3. October 2002. doi:10.1186/1471-2156-3-18. PMID 12361482.
- ↑ 7.0 7.1 "Q8IZJ6 · TDH_HUMAN". UniProt consortium. https://www.uniprot.org/uniprotkb/Q8IZJ6/entry.
- ↑ Lehninger principles of biochemistry, 8th edition (kindle version). New York: WH Freeman. 2021. p. 3357. ISBN 978-1-319-32238-0.
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