Threonine synthase

In enzymology, a threonine synthase (EC 4.2.3.1) is an enzyme that catalyzes the chemical reaction

O-phospho-L-homoserine + H₂O L-threonine + phosphate

Thus, the two substrates of this enzyme are O-phospho-L-homoserine and H₂O, whereas its two products are L-threonine and phosphate.

This enzyme belongs to the family of lyases, specifically those carbon-oxygen lyases acting on phosphates. The systematic name of this enzyme class is O-phospho-L-homoserine phosphate-lyase (adding water L-threonine-forming). Other names in common use include threonine synthetase, and O-phospho-L-homoserine phospho-lyase (adding water). This enzyme participates in glycine, serine and threonine metabolism and vitamin B₆ metabolism. It employs one cofactor, pyridoxal phosphate.

Structural studies

As of late 2007, 7 structures have been solved for this class of enzymes, with PDB accession codes 1UIM, 1UIN, 1V7C, 1VB3, 2C2B, 2C2G, and 2D1F.

References

• FLAVIN M, SLAUGHTER C (1960). "Purification and properties of threonine synthetase of Neurospora". J. Biol. Chem. 235: 1103–8. PMID 13823379.