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Literature summary extracted from

  • Harmon, J.M.; Bacikova, D.; Gable, K.; Gupta, S.D.; Han, G.; Sengupta, N.; Somashekarappa, N.; Dunn, T.M.
    Topological and functional characterization of the ssSPTs, small activating subunits of serine palmitoyltransferase (2013), J. Biol. Chem., 288, 10144-10153.
    View publication on PubMedView publication on EuropePMC

Activating Compound

EC Number Activating Compound Comment Organism Structure
2.3.1.50 small activating subunit of serine palmitoyltransferase ssSPT, the small subunits of human serine palmitoyltransferase (hssSPTs) are glycoproteins and activate the catalytic hLCB1/hLCB2 heterodimer. Two isoforms exist, ssSPTa and ssSPTb, a single amino acid, residue 25, difference between ssSPTa and ssSPTb is responsible for the acyl-CoA preference of heterotrimers containing each isoform. the role of the small activating subunits of serine palmitoyltransferase, ssSPTs, is to increase SPT activity without compromising substrate specificity. Activity and acyl-CoA selectivity of the ssSPTs reside in the conserved core. Deletion of the N-terminal 10 amino acids of small activating subunit of serine palmitoyltransferase isoforms ssSPTa or ssSPTb has no effect on the ability of the proteins to activate hLCB1/hLCB2a heterodimers sufficiently to complement growth of yeast lacking endogenous serine palmitoyltransferase. The region responsible for the acyl-CoA selectivity of ssSPTa lays between residues Ser11 and Glu27, the acyl-CoA selectivity does not lie in the C-terminal region of ssSPTb, overview Homo sapiens

Cloned(Commentary)

EC Number Cloned (Comment) Organism
2.3.1.50 expression of wild-type and mutant smalll subunits isoforms of serine palmitoyltransferase in yeast microsomes Homo sapiens

Protein Variants

EC Number Protein Variants Comment Organism
2.3.1.50 additional information deletion of the N-terminal 10 amino acids of small activating subunit of serine palmitoyltransferase isoforms ssSPTa or ssSPTb has no effect on the ability of the proteins to activate hLCB1/hLCB2a heterodimers sufficiently to complement growth of yeast lacking endogenous serine palmitoyltransferase. A chimera in which residues Glu27 to Pro54 of ssSPTa are replaced with residues Glu27 to Pro54 of ssSPTb or a chimera in which residues Glu27 to Gln68 of ssSPTa are replaced by residues Glu27 to Asn76 of ssSPTb is expressed in yeast, along with hLCB1 and hLCB2a, microsomal SPT assays show that both chimeric heterotrimers prefer palmitoyl-CoA as a substrate Homo sapiens

Localization

EC Number Localization Comment Organism GeneOntology No. Textmining
2.3.1.50 endoplasmic reticulum membrane the N-termini of the small activating subunit of serine palmitoyltransferase isoforms are locatedin the cytosol, their C-termini in the lumen, and they contain a single transmembrane domain Homo sapiens 5789
-

Natural Substrates/ Products (Substrates)

EC Number Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
2.3.1.50 palmitoyl-CoA + L-serine Homo sapiens
-
 CoA + 3-dehydro-D-sphinganine + CO2
-
 ?

Organism

EC Number Organism UniProt Comment Textmining
2.3.1.50 Homo sapiens
-
-
-

Posttranslational Modification

EC Number Posttranslational Modification Comment Organism
2.3.1.50 glycoprotein the small activating subunits of serine palmitoyltransferase, ssSPTs, are glycoproteins and are part of the enzyme complex Homo sapiens

Substrates and Products (Substrate)

EC Number Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2.3.1.50 palmitoyl-CoA + L-serine
-
 Homo sapiens CoA + 3-dehydro-D-sphinganine + CO2
-
 ?
2.3.1.50 stearoyl-CoA + L-serine
-
 Homo sapiens CoA + (2S)-2-amino-1-hydroxyicosan-3-one + CO2
-
 ?

Subunits

EC Number Subunits Comment Organism
2.3.1.50 More the small activating subunits of serine palmitoyltransferase, ssSPTs, are glycoproteins and are part of the enzyme complex Homo sapiens

Synonyms

EC Number Synonyms Comment Organism
2.3.1.50 serine palmitoyltransferase
-
 Homo sapiens

Temperature Optimum [°C]

EC Number Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
2.3.1.50 37
-
 assay at Homo sapiens

pH Optimum

EC Number pH Optimum Minimum pH Optimum Maximum Comment Organism
2.3.1.50 8.1
-
 assay at Homo sapiens

Cofactor

EC Number Cofactor Comment Organism Structure
2.3.1.50 pyridoxal 5'-phosphate
-
 Homo sapiens

General Information

EC Number General Information Comment Organism
2.3.1.50 metabolism eukaryotic serine palmitoyltransferase is an integral endoplasmic reticulum membrane protein that contains a head-to-tail heterodimer of two related but distinct subunits, LCB1 and LCB2, with a single catalytic site. There are additional subunits necessary for maximal activity as well as associated negative regulatory components Homo sapiens
2.3.1.50 physiological function the role of the small activating subunits of serine palmitoyltransferase, ssSPTs, is to increase SPT activity without compromising substrate specificity Homo sapiens