Homoserine kinase

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homoserine kinase
Homoserine kinase tetramer, Methanocaldococcus jannaschii
EC no.
CAS no.9026-58-8
IntEnzIntEnz view
ExPASyNiceZyme view
MetaCycmetabolic pathway
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO

In enzymology, a homoserine kinase (EC is an enzyme that catalyzes the chemical reaction

ATP + L-homoserine ADP + O-phospho-L-homoserine

Thus, the two substrates of this enzyme are ATP and L-homoserine, whereas its two products are ADP and O-phospho-L-homoserine.

This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing groups (phosphotransferases) with an alcohol group as acceptor. The systematic name of this enzyme class is ATP:L-homoserine O-phosphotransferase. Other names in common use include homoserine kinase (phosphorylating), and HSK. This enzyme participates in glycine, serine and threonine metabolism.

Structural studies[edit]

As of late 2007, 6 structures have been solved for this class of enzymes, with PDB accession codes 1FWK, 1FWL, 1H72, 1H73, 1H74, and 2PPQ.


  • FLAVIN M, SLAUGHTER C (1960). "Purification and properties of threonine synthetase of Neurospora". J. Biol. Chem. 235: 1103–8. PMID 13823379.
  • Watanabe Y, Konishi S, Shimura K (1957). "Biosynthesis of threonine from homoserine. VI. Homoserine kinase". J. Biochem. 44 (5): 299–307. doi:10.1093/oxfordjournals.jbchem.a126756.