Protein Overview and Biological Significance

INPP5F (Inositol Polyphosphate 5-Phosphatase F), also referred to as SAC2, is a member of the inositol polyphosphate 5-phosphatase family. This enzyme catalyzes the hydrolysis of the 5-phosphate group from phosphoinositide substrates, most notably phosphatidylinositol 3,5-bisphosphate [PI(3,5)P₂] and phosphatidylinositol 4,5-bisphosphate [PI(4,5)P₂]. These phosphoinositide species serve as critical second messengers that regulate membrane trafficking, endosomal sorting, and intracellular signal transduction.

Physiologically, INPP5F has been implicated in cardiac function, where loss of INPP5F activity is associated with pathological cardiac hypertrophy and altered PI3K–Akt signaling. Additionally, INPP5F participates in the regulation of autophagy and lysosomal homeostasis, making it a relevant target in studies of cardiomyopathy, neurodegeneration, and metabolic disease. Recombinant Human INPP5F Protein (rp373100) from Aladdin Scientific provides researchers with a well-characterized tool to interrogate these pathways in vitro.

Reconstitution and Handling Protocol

Proper reconstitution and handling of Recombinant Human INPP5F Protein are essential to preserve enzymatic activity and ensure experimental reproducibility. Follow these general best-practice guidelines, and always cross-reference the specific conditions indicated in the product datasheet supplied with each lot:

• Centrifugation before opening: Briefly centrifuge the vial at low speed (e.g., 1,000–2,000 × g for 10–15 seconds) to consolidate lyophilized or frozen material before opening.
• Reconstitution buffer: Reconstitute in an appropriate sterile buffer (commonly PBS pH 7.4 or a manufacturer-recommended buffer containing a carrier protein such as 0.1% BSA) to a working concentration. Consult the product datasheet for the recommended reconstitution volume and buffer composition.
• Gentle mixing: Mix gently by pipetting or swirling; avoid vortexing, which can denature the protein and reduce activity.
• Aliquoting: Immediately prepare single-use aliquots to minimize freeze-thaw cycles. Each freeze-thaw event can degrade enzymatic activity.
• Storage: Store working aliquots at -80 °C. Short-term storage (up to 1 week) may be acceptable at -20 °C; verify with the product datasheet.
• Equilibration: Before use, thaw aliquots on ice and allow to equilibrate briefly at room temperature immediately prior to assay setup.

Note: Specific buffer compositions, reconstitution volumes, and activity data are lot-dependent. Always refer to the certificate of analysis (CoA) and product datasheet provided with your shipment.

Recommended Applications

Recombinant Human INPP5F Protein is suitable for a range of in vitro research applications. Representative uses include:

• Enzymatic activity assays: Quantification of 5-phosphatase activity toward PI(3,5)P₂ and PI(4,5)P₂ substrates using colorimetric or fluorometric phosphate-release assays.
• Protein–protein interaction studies: Pull-down or co-immunoprecipitation experiments to identify INPP5F binding partners involved in endosomal trafficking or cardiac signaling complexes.
• Western blot standard: Use as a positive control or molecular weight standard in immunoblotting experiments with anti-INPP5F antibodies.
• Drug screening: Serve as the target enzyme in high-throughput or medium-throughput inhibitor screening campaigns aimed at modulating phosphoinositide metabolism.
• Structural and biophysical studies: Substrate for biophysical characterization techniques such as isothermal titration calorimetry (ITC) or surface plasmon resonance (SPR) to study ligand binding.

Always validate the protein lot for the specific application intended, using activity data from the CoA as a baseline reference.

Quality, Purity, and Lot-to-Lot Consistency

Aladdin Scientific's Recombinant Human INPP5F Protein (rp373100) is manufactured under controlled conditions to deliver consistent purity and biological activity across lots. Key quality attributes to verify upon receipt include:

• Purity: Assessed by SDS-PAGE and/or HPLC. Target purity specifications are provided on the product datasheet; review the CoA for lot-specific results.
• Biological activity: Confirmed by enzymatic assay demonstrating 5-phosphatase activity. Specific activity values (units/mg) are lot-dependent and documented in the CoA.
• Endotoxin level: Tested by LAL (Limulus Amebocyte Lysate) assay; low endotoxin specifications are important for cell-based assays.
• Molecular integrity: Verified by reducing and non-reducing SDS-PAGE to confirm expected molecular weight and absence of major degradation bands.

If the received product does not meet the stated specifications, contact Aladdin Scientific customer service immediately with the lot number and CoA for resolution.

Troubleshooting Common Issues

If unexpected results are obtained when working with Recombinant Human INPP5F Protein, consider the following troubleshooting steps:

• Low or absent enzymatic activity: Confirm the protein was stored correctly and that freeze-thaw cycles were minimized. Verify that assay conditions (buffer, pH, cofactors, substrate concentration) match recommended parameters. Check that the substrate used is appropriate for INPP5F (PI(3,5)P₂ or PI(4,5)P₂).
• Protein precipitation or aggregation: Ensure reconstitution was performed with the recommended buffer and that the protein was not exposed to extreme temperatures or vortexing. Adding a carrier protein (e.g., 0.1% BSA) can improve stability.
• High background in binding assays: Include appropriate blocking steps and negative controls. Confirm antibody specificity if immunodetection is employed.
• Unexpected molecular weight on gel: Confirm whether reducing or non-reducing conditions were used, as disulfide-bonded forms may migrate differently. Post-translational modifications may also affect apparent molecular weight.
• Lot-to-lot variability: Always run an in-house activity standard alongside new lots to normalize results across experiments.

For unresolved technical issues, contact Aladdin Scientific Technical Support, providing the product SKU (rp373100), lot number, CoA, and a detailed description of the experimental conditions.