EC - Phosphoserine transaminase

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IntEnz Enzyme Nomenclature


Accepted name:
phosphoserine transaminase
Other names:
3-phosphoserine aminotransferase
L-phosphoserine aminotransferase
hydroxypyruvic phosphate—glutamic transaminase
phosphohydroxypyruvate transaminase
phosphohydroxypyruvic—glutamic transaminase
phosphoserine aminotransferase
3-O-phospho-L-serine:2-oxoglutarate aminotransferase
3PHP transaminase
Systematic name:
O-phospho-L-serine:2-oxoglutarate aminotransferase




A pyridoxal-phosphate protein. This enzyme catalyses the second step in the phosphorylated pathway of serine biosynthesis in Escherichia coli [2,3]. It also catalyses the third step in the biosynthesis of the coenzyme pyridoxal 5'-phosphate in E. coli (using Reaction 2 above) [3]. In E. coli, pyridoxal 5'-phosphate is synthesized de novo by a pathway that involves EC (erythrose-4-phosphate dehydrogenase), EC (4-phosphoerythronate dehydrogenase), EC (phosphoserine transaminase), EC (4-hydroxythreonine-4-phosphate dehydrogenase), EC (pyridoxine 5'-phosphate synthase) and EC (with pyridoxine 5'-phosphate as substrate). Pyridoxal phosphate is the cofactor for both activities and therefore seems to be involved in its own biosynthesis [4]. Non-phosphorylated forms of serine and threonine are not substrates [4].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , DIAGRAM , DIAGRAM , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , NIST 74 , UniPathway
Protein domains and families: PROSITE:PDOC00514
Structural data: CSA , EC2PDB
Gene Ontology: GO:0004648
CAS Registry Number: 9030-90-4
UniProtKB/Swiss-Prot: (273) [show] [UniProt]


  1. Hirsch, H. and Greenberg, D.M.
    Studies on phosphoserine aminotransferase of sheep brain.
    J. Biol. Chem. 242: 2283-2287 (1967). [PMID: 6022873]
  2. Pizer, L.I.
    The pathway and control of serine biosynthesis in Escherichia coli.
    J. Biol. Chem. 238: 3934-3944 (1963). [PMID: 14086727]
  3. Zhao, G. and Winkler, M.E.
    A novel α-ketoglutarate reductase activity of the serA-encoded 3-phosphoglycerate dehydrogenase of Escherichia coli K-12 and its possible implications for human 2-hydroxyglutaric aciduria.
    J. Bacteriol. 178: 232-239 (1996). [PMID: 8550422]
  4. Drewke, C., Klein, M., Clade, D., Arenz, A., Müller, R., Leistner, E.
    4-O-phosphoryl-L-threonine, a substrate of the pdxC(serC) gene product involved in vitamin B6 biosynthesis.
    FEBS Lett. 390: 179-182 (1996). [PMID: 8706854]
  5. Zhao, G. and Winkler, M.E.
    4-Phospho-hydroxy-L-threonine is an obligatory intermediate in pyridoxal 5'-phosphate coenzyme biosynthesis in Escherichia coli K-12.
    FEMS Microbiol. Lett. 135: 275-280 (1996). [PMID: 8595869]

[EC created 1972, modified 2006]