Serine C-palmitoyltransferase

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serine C-palmitoyltransferase
Identifiers
EC number 2.3.1.50
CAS number 62213-50-7
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 / EGO
Serine palmitoyltransferase
SPT 2jg2.png
Crystallographic structure of serine palmitoyltransferase from S. paucimobilis. The cofactor PLP is visible in the center.[1]
Identifiers
Symbol ?
PDB 2JG2 (RCSB PDB PDBe PDBj)
UniProt Q93UV0
Other data
serine palmitoyltransferase, long chain base subunit 1
Identifiers
Symbol SPTLC1
Alt. symbols HSN1
Entrez 10558
HUGO 11277
OMIM 605712
RefSeq NM_006415
UniProt O15269
Other data
Locus Chr. 9 q22.31
serine palmitoyltransferase, long chain base subunit 2
Identifiers
Symbol SPTLC2
Entrez 9517
HUGO 11278
OMIM 605713
RefSeq NM_004863
UniProt O15270
Other data
Locus Chr. 14 q24.3
serine palmitoyltransferase, long chain base subunit 3
Identifiers
Symbol SPTLC3
Alt. symbols C20orf38, SPTLC2L
Entrez 55304
HUGO 16253
OMIM 611120
RefSeq NM_018327
UniProt Q9NUV7
Other data
Locus Chr. 20 p12.1

In enzymology, a serine C-palmitoyltransferase (EC 2.3.1.50) is an enzyme that catalyzes the chemical reaction:[2][3]

palmitoyl-CoA + L-serine \rightleftharpoons CoA + 3-dehydro-D-sphinganine + CO2

Thus, the two substrates of this enzyme are palmitoyl-CoA and L-serine, whereas its 3 products are CoA, 3-dehydro-D-sphinganine, and CO2.[4][5] This reaction is a key step in the biosynthesis of sphingosine which is a precursor of many other sphingolipids.[3]

This enzyme belongs to the family of transferases, specifically those acyltransferases transferring groups other than aminoacyl groups. The systematic name of this enzyme class is palmitoyl-CoA:L-serine C-palmitoyltransferase (decarboxylating). Other names in common use include serine palmitoyltransferase, SPT, 3-oxosphinganine synthetase, and acyl-CoA:serine C-2 acyltransferase decarboxylating. This enzyme participates in sphingolipid metabolism. It employs one cofactor, pyridoxal phosphate.

Species distribution[edit]

This enzyme is expressed in a large number of species from bacteria to humans. The bacterial enzyme is a water soluble homodimer[2] whereas in eukaryotes the enzyme is a heterodimer which is anchored to the endoplasmic reticulum.[3] Humans and other mammals express three paralogous subunits SPTLC1, SPTLC2, and SPTLC3. It was originally proposed that the functional human enzyme is a heterodimer between a SPTLC1 subunit and a second subunit which is either SPTLC2 or SPTLC3.[6] However more recent data suggest that the enzyme may exist as a larger complex, possibly an octamer, comprising all three subunits.[7]

Structural studies[edit]

As of late 2007, two structures have been solved for this class of enzymes, with PDB accession codes 2JG2 and 2JGT.[1]

References[edit]

  1. ^ a b PDB 2JG2; Yard BA, Carter LG, Johnson KA, Overton IM, Dorward M, Liu H, McMahon SA, Oke M, Puech D, Barton GJ, Naismith JH, Campopiano DJ (July 2007). "The structure of serine palmitoyltransferase; gateway to sphingolipid biosynthesis". J. Mol. Biol. 370 (5): 870–86. doi:10.1016/j.jmb.2007.04.086. PMID 17559874. 
  2. ^ a b Ikushiro H, Hayashi H, Kagamiyama H (April 2003). "Bacterial serine palmitoyltransferase: a water-soluble homodimeric prototype of the eukaryotic enzyme". Biochim. Biophys. Acta 1647 (1-2): 116–20. doi:10.1016/S1570-9639(03)00074-8. PMID 12686119. 
  3. ^ a b c Hanada K (June 2003). "Serine palmitoyltransferase, a key enzyme of sphingolipid metabolism". Biochim. Biophys. Acta 1632 (1-3): 16–30. doi:10.1016/S1388-1981(03)00059-3. PMID 12782147. 
  4. ^ Brady RN, Di Mari SJ, Snell EE (January 1969). "Biosynthesis of sphingolipid bases. 3. Isolation and characterization of ketonic intermediates in the synthesis of sphingosine and dihydrosphingosine by cell-free extracts of Hansenula ciferri". J. Biol. Chem. 244 (2): 491–6. PMID 4388074. 
  5. ^ Stoffel W, LeKim D, Sticht G (May 1968). "Biosynthesis of dihydrosphingosine in vitro". Hoppe-Seyler's Z. Physiol. Chem. 349 (5): 664–70. doi:10.1515/bchm2.1968.349.1.664. PMID 4386961. 
  6. ^ Hornemann T, Richard S, Rütti MF, Wei Y, von Eckardstein A (December 2006). "Cloning and initial characterization of a new subunit for mammalian serine-palmitoyltransferase". J. Biol. Chem. 281 (49): 37275–81. doi:10.1074/jbc.M608066200. PMID 17023427. 
  7. ^ Hornemann T, Wei Y, von Eckardstein A (July 2007). "Is the mammalian serine palmitoyltransferase a high-molecular-mass complex?". Biochem. J. 405 (1): 157–64. doi:10.1042/BJ20070025. PMC 1925250. PMID 17331073.