What Is INPP1 and Why Does It Matter?

Inositol polyphosphate 1-phosphatase (INPP1) is a magnesium-dependent phosphomonoesterase encoded by the INPP1 gene in humans. It catalyzes the hydrolysis of inositol 1-phosphate (Ins1P) and inositol 1,4-bisphosphate (Ins(1,4)P2) to yield free inositol, a critical step in recycling inositol for phosphatidylinositol biosynthesis.

INPP1 is notably sensitive to inhibition by lithium ions (Li⁺), which has made it a key target for studying the mechanism of action of lithium therapy in bipolar disorder. By blocking INPP1 (and the related enzyme IMPase), lithium is proposed to deplete free inositol and thereby dampen overactive phosphoinositide signaling — the basis of the inositol depletion hypothesis.

Beyond neuropsychiatric research, INPP1 activity has implications for metabolic regulation, cellular stress responses, and developmental biology, making recombinant INPP1 protein a valuable reagent across multiple disciplines.

Protein Properties and Quality Attributes

Recombinant Human INPP1 Protein (rp365232) is produced using recombinant expression technology to deliver a functionally active form of the human enzyme. Key biochemical characteristics of INPP1 include:

• Enzyme class: Phosphomonoesterase (EC 3.1.3.57)
• Metal cofactor requirement: Magnesium (Mg²⁺) dependent; activity is abolished by EDTA or EGTA chelation
• Substrate specificity: Acts on Ins1P and Ins(1,4)P2; does not efficiently hydrolyze Ins(1,4,5)P3 or higher inositol phosphates
• Inhibitor sensitivity: Competitively inhibited by lithium at physiologically relevant concentrations
• Molecular weight: Approximately 44 kDa (monomer); verify with product datasheet

For specific purity, endotoxin level, specific activity values, and formulation details, please refer to the official product datasheet available on the Aladdin Scientific product page for rp365232. All lot-specific quality data are provided with each shipment.

Recommended Handling, Storage, and Reconstitution Protocol

Proper handling of Recombinant Human INPP1 Protein is essential to maintain enzymatic activity and ensure reproducible experimental results. Follow these guidelines:

Storage

• Store lyophilized protein at –20 °C or –80 °C (as specified on the datasheet) in a desiccated environment.
• Avoid repeated freeze–thaw cycles; aliquot upon first reconstitution.
• Liquid formulations should be stored at –80 °C for long-term stability.

Reconstitution

• Reconstitute lyophilized protein in sterile, ultrapure water or the buffer specified in the product datasheet.
• Allow the vial to equilibrate to room temperature before opening.
• Gently mix by pipetting; do not vortex.
• Centrifuge briefly to collect contents before opening the vial if lyophilized cake has shifted.

Working Conditions

• Include Mg²⁺ (typically 1–10 mM MgCl₂) in all assay buffers; INPP1 is Mg²⁺-dependent.
• Avoid EDTA-containing buffers, which chelate Mg²⁺ and abolish activity.
• Optimal pH range is typically 7.5–8.5; confirm with the datasheet.
• Add carrier protein (e.g., 0.1% BSA) when diluting to low concentrations to prevent adsorptive loss.

Note: All specific buffer compositions, reconstitution volumes, and recommended working concentrations should be verified against the lot-specific datasheet supplied with rp365232.

Research Applications of Recombinant Human INPP1 Protein

Recombinant Human INPP1 Protein (rp365232) supports a wide range of in vitro research applications:

• Enzyme activity assays: Measure INPP1-mediated phosphate release from Ins1P or Ins(1,4)P2 substrates using colorimetric or fluorometric phosphate detection reagents.
• Inhibitor and drug screening: Use as a biochemical target for high-throughput or focused screening of small-molecule inhibitors, including lithium-mimetic compounds relevant to bipolar disorder research.
• Inositol phosphate pathway reconstitution: Incorporate into cell-free systems to study the dynamics of the phosphatidylinositol cycle.
• Structural and biophysical studies: Suitable for X-ray crystallography, cryo-EM, or biophysical interaction studies when combined with appropriate sample preparation.
• Antibody validation: Use as a positive control antigen to validate anti-INPP1 antibodies in Western blot, ELISA, or immunoprecipitation workflows.
• Comparative enzymology: Compare kinetics with related phosphatases (IMPase, INPP5) to dissect pathway specificity.

Researchers are encouraged to optimize assay conditions for their specific experimental context and to consult the product datasheet for recommended application notes.

Regulatory Status and Quality Assurance

Recombinant Human INPP1 Protein (rp365232) supplied by Aladdin Scientific is intended for research use only (RUO) and is not approved for diagnostic, therapeutic, or clinical use in humans or animals.

Quality attributes assessed for each lot may include:

• Purity by SDS-PAGE or HPLC
• Endotoxin level by LAL assay
• Specific enzymatic activity
• Identity confirmation by mass spectrometry or Western blot

All quality data are documented in the Certificate of Analysis (CoA) provided with each shipment. Researchers should retain the CoA for experimental records. For additional technical support, batch-specific data requests, or custom production inquiries, contact Aladdin Scientific technical support.