Homoserine

l-Homoserine

Names
IUPAC name (S)-2-Amino-4-hydroxybutanoic acid
Identifiers
CAS Number	672-15-1 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:30653 Y
ChEMBL	ChEMBL11722 N
ChemSpider	758 Y
ECHA InfoCard	100.010.538
EC Number	211-590-6
PubChem CID	779
UNII	6KA95X0IVO Y
CompTox Dashboard (EPA)	DTXSID5075159
InChI InChI=1S/C4H9NO3/c5-3(1-2-6)4(7)8/h3,6H,1-2,5H2,(H,7,8) Y Key: UKAUYVFTDYCKQA-UHFFFAOYSA-N Y InChI=1/C4H9NO3/c5-3(1-2-6)4(7)8/h3,6H,1-2,5H2,(H,7,8) Key: UKAUYVFTDYCKQA-UHFFFAOYAZ
SMILES O=C(O)C(N)CCO
Properties
Chemical formula	C4H9NO3
Molar mass	119.12 g/mol
Melting point	203 °C (decomposes)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Homoserine (also called isothreonine) is an α-amino acid with the chemical formula HO₂CCH(NH₂)CH₂CH₂OH. L-Homoserine is not one of the common amino acids encoded by DNA. It differs from the proteinogenic amino acid serine by insertion of an additional -CH₂- unit into the backbone. Homoserine, or its lactone form, is the product of a cyanogen bromide cleavage of a peptide by degradation of methionine.

Homoserine is an intermediate in the biosynthesis of three essential amino acids: methionine, threonine (an isomer of homoserine), and isoleucine.^[1] Its complete biosynthetic pathway includes glycolysis, the tricarboxylic acid (TCA) or citric acid cycle (Krebs cycle), and the aspartate metabolic pathway. It forms by two reductions of aspartic acid via the intermediacy of aspartate semialdehyde.^[2] Specifically, the enzyme homoserine dehydrogenase, in association with NADPH, catalyzes a reversible reaction that interconverts L-aspartate-4-semialdehyde to L-homoserine. Then, two other enzymes, homoserine kinase and homoserine O-succinyltransferase use homoserine as a substrate and produce phosphohomoserine and O-succinyl homoserine respectively.^[3]