Q6AYK3 · INO1_RAT
- ProteinInositol-3-phosphate synthase 1
- GeneIsyna1
- StatusUniProtKB reviewed (Swiss-Prot)
- Organism
- Amino acids557 (go to sequence)
- Protein existenceEvidence at protein level
- Annotation score5/5
Function
function
Key enzyme in myo-inositol biosynthesis pathway that catalyzes the conversion of glucose 6-phosphate to 1-myo-inositol 1-phosphate in a NAD-dependent manner (PubMed:23504145, PubMed:6773943, PubMed:885873). Rate-limiting enzyme in the synthesis of all inositol-containing compounds (By similarity).
Isoform 1
Key enzyme in myo-inositol biosynthesis pathway that catalyzes the conversion of glucose 6-phosphate to 1-myo-inositol 1-phosphate in a NAD-dependent manner.
Isoform 2
Competitively inhibits the function of isoform 1, presumably by competing for NAD cofactor.
Catalytic activity
- D-glucose 6-phosphate = 1D-myo-inositol 3-phosphate
Isoform 1
D-glucose 6-phosphate = 1D-myo-inositol 3-phosphate
Cofactor
Protein has several cofactor binding sites:
Isoform 1
NAD+ (UniProtKB | Rhea| CHEBI:57540 )Isoform 2
NAD+ (UniProtKB | Rhea| CHEBI:57540 )Activity regulation
Inhibited by 2-deoxyglucitol 6-phosphate (dgtolP) and 2-deoxy-D-glucose 6-phosphate (PubMed:6773943).
Inhibited by copper, mercury, cadmium, zinc and copper ions (PubMed:6773943).
Activated by potassium and ammonium ions (PubMed:6773943).
Inhibited by copper, mercury, cadmium, zinc and copper ions (PubMed:6773943).
Activated by potassium and ammonium ions (PubMed:6773943).
Kinetics
KM | SUBSTRATE | pH | TEMPERATURE[C] | NOTES | EVIDENCE | |
---|---|---|---|---|---|---|
3.89 mM | D-glucose 6-phosphate | 7.4 | 37 |
pH Dependence
Optimum pH is 7.7.
Pathway
Polyol metabolism; myo-inositol biosynthesis; myo-inositol from D-glucose 6-phosphate: step 1/2.
Features
Showing features for binding site.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Binding site | 67 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 68 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 69 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 70 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 141 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 177 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 178 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 188 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 191 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 228 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 229 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 230 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 231 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 278 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 279 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 303 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 306 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 337 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 338 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 339 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 352 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 390 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 391 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 419 | NAD+ (UniProtKB | ChEBI) | |||
Binding site | 420 | NAD+ (UniProtKB | ChEBI) | |||
GO annotations
Aspect | Term | |
---|---|---|
Cellular Component | cytoplasm | |
Molecular Function | inositol-3-phosphate synthase activity | |
Biological Process | inositol biosynthetic process | |
Biological Process | negative regulation of inositol biosynthetic process | |
Biological Process | phospholipid biosynthetic process |
Keywords
- Molecular function
- Biological process
- Ligand
Enzyme and pathway databases
Names & Taxonomy
Protein names
- Recommended nameInositol-3-phosphate synthase 1
- EC number
- Short namesIPS 1
- Alternative names
Gene names
Organism names
- Organism
- Strain
- Taxonomic lineageEukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Mammalia > Eutheria > Euarchontoglires > Glires > Rodentia > Myomorpha > Muroidea > Muridae > Murinae > Rattus
Accessions
- Primary accessionQ6AYK3
Proteomes
Organism-specific databases
Subcellular Location
PTM/Processing
Features
Showing features for chain, modified residue.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Chain | PRO_0000324631 | 1-557 | Inositol-3-phosphate synthase 1 | ||
Modified residue | 279 | Phosphoserine | |||
Modified residue | 357 | Phosphoserine | |||
Modified residue | 524 | Phosphoserine | |||
Post-translational modification
Phosphorylation at Ser-524 does not appear to affect enzyme activity, and is detected in brain and testis.
Keywords
- PTM
Proteomic databases
PTM databases
Expression
Tissue specificity
Expressed in testis, brain and epididymis (at protein level) (PubMed:19188364, PubMed:23504145, PubMed:6773943, PubMed:885873). Moderately expressed in brain, lung, liver, and kidney (PubMed:19188364).
Low expression in heart and spleen (PubMed:19188364).
Very low expression in skeletal muscle (PubMed:19188364).
Low expression in heart and spleen (PubMed:19188364).
Very low expression in skeletal muscle (PubMed:19188364).
Isoform 1
Expressed in testis, spleen, heart, brainstem, hippocampus, cerebellum, cortex and amygdala (PubMed:19188364).
Absent or very lowly expressed in intestine, lung and muscle (PubMed:19188364).
Absent or very lowly expressed in intestine, lung and muscle (PubMed:19188364).
Isoform 2
Expressed in intestine, lung, liver, muscle, testis, spleen, brainstem, hippocampus, cerebellum, cortex and amygdala (PubMed:19188364).
Absent or lowly expressed in heart and kidney (PubMed:19188364).
Absent or lowly expressed in heart and kidney (PubMed:19188364).
Isoform 3
Expressed in intestine (at protein level).
Gene expression databases
Structure
Family & Domains
Features
Showing features for region, compositional bias.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Region | 514-557 | Disordered | |||
Compositional bias | 529-557 | Polar residues | |||
Sequence similarities
Belongs to the myo-inositol 1-phosphate synthase family.
Phylogenomic databases
Family and domain databases
Sequence & Isoforms
- Sequence statusComplete
This entry describes 3 isoforms produced by Alternative splicing.
Q6AYK3-1
This isoform has been chosen as the canonical sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.
- Name1
- Synonymsalpha
- Length557
- Mass (Da)60,884
- Last updated2008-03-18 v2
- ChecksumF351B16D74E94281
Q6AYK3-3
- Name2
- Synonymsgammac
- Differences from canonical
- 139-557: GWDISSLNLAEAMRRAQVLDCGLQEQLWPHMESLRPRPSVYIPEFIAANQTARADNLIPGTRAQQLEQIRKDIRDFRSSAGLDKVIVLWTANTERFCEVVPGRNDTAENLLRTIQLGLEVSPSTLFAVASILEGCAFLNGSPQNTLVPGALELASQRHVFVGGDDFKSGQTKVKSVLVDFLIGSGLKTMSIVSYNHLGNNDGQNLSAPLQFRSKEVTKSSVVDDMVQSNRVLYAPGEEPDHCVVIKYVPYVGDSKRALDEYTSELMLGGTNTLVLHNTCEDSLLAAPIMLDLVLLTELCQRVSFCTDSDPEPQGFHPVLSVLSFLFKAPLVPPGSPVVNALFRQRSCIENIFRACVGLPPQNHMLLEHKMERPFPGIKPEEVKATSPLPCKKESTPATNGCTGDANGHTQAPTPELSTA → GGQSLGMGWG
Q6AYK3-5
- Name3
- Differences from canonical
- 492-557: Missing
Features
Showing features for alternative sequence, compositional bias.
Type | ID | Position(s) | Description | ||
---|---|---|---|---|---|
Alternative sequence | VSP_061662 | 139-557 | in isoform 2 | ||
Alternative sequence | VSP_061663 | 492-557 | in isoform 3 | ||
Compositional bias | 529-557 | Polar residues | |||
Keywords
- Coding sequence diversity
- Technical term
Sequence databases
Nucleotide Sequence | Protein Sequence | Molecule Type | Status | |
---|---|---|---|---|
AABR03100304 EMBL· GenBank· DDBJ | - | Genomic DNA | No translation available. |