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MGP005194

UniProt Annotations

Entry Information
Gene Nameinositol-3-phosphate synthase 1
Protein EntryINO1_HUMAN
UniProt IDQ9NPH2
SpeciesHuman
Comments
Comment typeDescription
Alternative ProductsEvent=Alternative splicing; Named isoforms=3; Name=1; IsoId=Q9NPH2-1; Sequence=Displayed; Name=2; IsoId=Q9NPH2-2; Sequence=VSP_032324; Name=3; IsoId=Q9NPH2-3; Sequence=VSP_046065; Note=No experimental confirmation available.;
Biophysicochemical PropertiesKinetic parameters: KM=0.57 mM for 6-phosphate {ECO:0000269|PubMed:15024000}; KM=8 uM for NAD {ECO:0000269|PubMed:15024000}; pH dependence: Optimum pH is 8.0. {ECO:0000269|PubMed:15024000};
Catalytic ActivityD-glucose 6-phosphate = 1D-myo-inositol 3- phosphate. {ECO:0000269|PubMed:15024000}.
CofactorName=NAD(+); Xref=ChEBI:CHEBI:57540; Evidence={ECO:0000269|PubMed:15024000};
Enzyme RegulationInhibited by mood-stabilizing drugs such as valproate (VPA) and lithium. {ECO:0000269|PubMed:17901568, ECO:0000269|PubMed:17988368}.
FunctionKey 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. Rate-limiting enzyme in the synthesis of all inositol-containing compounds. {ECO:0000269|PubMed:15024000}.
InductionBy glucose and lovastain. Up-regulation is prevented by mevalonic acid, farnesol, and geranylgeraniol. Up-regulated by E2F1. {ECO:0000269|PubMed:12941308, ECO:0000269|PubMed:15464731}.
PathwayPolyol metabolism; myo-inositol biosynthesis; myo- inositol from D-glucose 6-phosphate: step 1/2.
Sequence CautionSequence=AAP97151.1; Type=Frameshift; Positions=82, 85, 496; Evidence={ECO:0000305};
SimilarityBelongs to the myo-inositol 1-phosphate synthase family. {ECO:0000305}.
Subcellular LocationCytoplasm {ECO:0000250}.
Tissue SpecificityHighly expressed in testis, ovary, heart, placenta and pancreas. Weakly expressed in blood leukocyte, thymus, skeletal muscle and colon. {ECO:0000269|PubMed:12941308}.
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