Q6AYK3 · INO1_RAT

  • Protein
    Inositol-3-phosphate synthase 1
  • Gene
    Isyna1
  • Status
    UniProtKB reviewed (Swiss-Prot)
  • Amino acids
  • Protein existence
    Evidence at protein level
  • Annotation score
    5/5

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

Cofactor

Protein has several cofactor binding sites:
NAD+ (UniProtKB | Rhea| CHEBI:57540 )

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).

Kinetics

KM SUBSTRATE pH TEMPERATURE[C] NOTES EVIDENCE
3.89 mMD-glucose 6-phosphate7.437

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.

TypeIDPosition(s)Description
Binding site67NAD+ (UniProtKB | ChEBI)
Binding site68NAD+ (UniProtKB | ChEBI)
Binding site69NAD+ (UniProtKB | ChEBI)
Binding site70NAD+ (UniProtKB | ChEBI)
Binding site141NAD+ (UniProtKB | ChEBI)
Binding site177NAD+ (UniProtKB | ChEBI)
Binding site178NAD+ (UniProtKB | ChEBI)
Binding site188NAD+ (UniProtKB | ChEBI)
Binding site191NAD+ (UniProtKB | ChEBI)
Binding site228NAD+ (UniProtKB | ChEBI)
Binding site229NAD+ (UniProtKB | ChEBI)
Binding site230NAD+ (UniProtKB | ChEBI)
Binding site231NAD+ (UniProtKB | ChEBI)
Binding site278NAD+ (UniProtKB | ChEBI)
Binding site279NAD+ (UniProtKB | ChEBI)
Binding site303NAD+ (UniProtKB | ChEBI)
Binding site306NAD+ (UniProtKB | ChEBI)
Binding site337NAD+ (UniProtKB | ChEBI)
Binding site338NAD+ (UniProtKB | ChEBI)
Binding site339NAD+ (UniProtKB | ChEBI)
Binding site352NAD+ (UniProtKB | ChEBI)
Binding site390NAD+ (UniProtKB | ChEBI)
Binding site391NAD+ (UniProtKB | ChEBI)
Binding site419NAD+ (UniProtKB | ChEBI)
Binding site420NAD+ (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentcytoplasm
Molecular Functioninositol-3-phosphate synthase activity
Biological Processinositol biosynthetic process
Biological Processnegative regulation of inositol biosynthetic process
Biological Processphospholipid biosynthetic process

Keywords

Enzyme and pathway databases

Names & Taxonomy

Protein names

  • Recommended name
    Inositol-3-phosphate synthase 1
  • EC number
  • Short names
    IPS 1
  • Alternative names
    • Myo-inositol 1-phosphate synthase (MI-1-P synthase; MIP synthase)

Gene names

    • Name
      Isyna1
    • Synonyms
      Ino1

Organism names

  • Taxonomic identifier
  • Strain
    • Brown Norway
  • Taxonomic lineage
    Eukaryota > Metazoa > Chordata > Craniata > Vertebrata > Euteleostomi > Mammalia > Eutheria > Euarchontoglires > Glires > Rodentia > Myomorpha > Muroidea > Muridae > Murinae > Rattus

Accessions

  • Primary accession
    Q6AYK3

Proteomes

Organism-specific databases

Subcellular Location

Keywords

PTM/Processing

Features

Showing features for chain, modified residue.

Type
IDPosition(s)Description
ChainPRO_00003246311-557Inositol-3-phosphate synthase 1
Modified residue279Phosphoserine
Modified residue357Phosphoserine
Modified residue524Phosphoserine

Post-translational modification

Phosphorylation at Ser-524 does not appear to affect enzyme activity, and is detected in brain and testis.

Keywords

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).

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).

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).

Isoform 3

Expressed in intestine (at protein level).

Gene expression databases

Interaction

Subunit

Homotrimer.

Protein-protein interaction databases

Structure

Family & Domains

Features

Showing features for region, compositional bias.

Type
IDPosition(s)Description
Region514-557Disordered
Compositional bias529-557Polar residues

Sequence similarities

Phylogenomic databases

Family and domain databases

Sequence & Isoforms

Align isoforms (3)
  • Sequence status
    Complete

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.

  • Name
    1
  • Synonyms
    alpha
  • See also
    sequence in UniParc or sequence clusters in UniRef
  • Length
    557
  • Mass (Da)
    60,884
  • Last updated
    2008-03-18 v2
  • Checksum
    F351B16D74E94281
MEPAAEILVDSPDVIFGPEAIEARYEYRTTRVSREGGVLRVRPTATRFTFRTARQVPRLGVMLVGWGGNNGSTLTAAVLANRLRLTWPTRTGRKEANYYGSLTQAGTVNLGLDGDGREVFVPFSALLPMVAPNDLVFDGWDISSLNLAEAMRRAQVLDCGLQEQLWPHMESLRPRPSVYIPEFIAANQTARADNLIPGTRAQQLEQIRKDIRDFRSSAGLDKVIVLWTANTERFCEVVPGRNDTAENLLRTIQLGLEVSPSTLFAVASILEGCAFLNGSPQNTLVPGALELASQRHVFVGGDDFKSGQTKVKSVLVDFLIGSGLKTMSIVSYNHLGNNDGQNLSAPLQFRSKEVTKSSVVDDMVQSNRVLYAPGEEPDHCVVIKYVPYVGDSKRALDEYTSELMLGGTNTLVLHNTCEDSLLAAPIMLDLVLLTELCQRVSFCTDSDPEPQGFHPVLSVLSFLFKAPLVPPGSPVVNALFRQRSCIENIFRACVGLPPQNHMLLEHKMERPFPGIKPEEVKATSPLPCKKESTPATNGCTGDANGHTQAPTPELSTA

Q6AYK3-3

  • Name
    2
  • Synonyms
    gammac
  • See also
    sequence in UniParc or sequence clusters in UniRef
  • Differences from canonical
    • 139-557: GWDISSLNLAEAMRRAQVLDCGLQEQLWPHMESLRPRPSVYIPEFIAANQTARADNLIPGTRAQQLEQIRKDIRDFRSSAGLDKVIVLWTANTERFCEVVPGRNDTAENLLRTIQLGLEVSPSTLFAVASILEGCAFLNGSPQNTLVPGALELASQRHVFVGGDDFKSGQTKVKSVLVDFLIGSGLKTMSIVSYNHLGNNDGQNLSAPLQFRSKEVTKSSVVDDMVQSNRVLYAPGEEPDHCVVIKYVPYVGDSKRALDEYTSELMLGGTNTLVLHNTCEDSLLAAPIMLDLVLLTELCQRVSFCTDSDPEPQGFHPVLSVLSFLFKAPLVPPGSPVVNALFRQRSCIENIFRACVGLPPQNHMLLEHKMERPFPGIKPEEVKATSPLPCKKESTPATNGCTGDANGHTQAPTPELSTA → GGQSLGMGWG

Q6AYK3-5

Features

Showing features for alternative sequence, compositional bias.

Type
IDPosition(s)Description
Alternative sequenceVSP_061662139-557in isoform 2
Alternative sequenceVSP_061663492-557in isoform 3
Compositional bias529-557Polar residues

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AABR03100304
EMBL· GenBank· DDBJ
-Genomic DNA No translation available.

Genome annotation databases

Similar Proteins

Disclaimer

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