Enterostatin Human (APGPR) Handling & Reconstitution Protocol

Enterostatin human is a biologically active pentapeptide (Ala-Pro-Gly-Pro-Arg) derived from the N-terminal activation peptide of procolipase, recognized for its role in regulating dietary fat intake and satiety signaling in research models.

Amino Acid Sequence

Ala-Pro-Gly-Pro-Arg (APGPR)

Peptide Length

5 amino acids (pentapeptide)

SKU

E118905

Biological Origin

Human procolipase N-terminal activation peptide

Primary Research Application

Satiety signaling and dietary fat intake regulation studies

Recommended Storage

-20 °C, desiccated; avoid repeated freeze-thaw cycles

Materials Required

Before beginning, gather the following materials:

• Enterostatin human (SKU E118905, Ala-Pro-Gly-Pro-Arg)
• Sterile water for injection or phosphate-buffered saline (PBS, pH 7.4)
• Low-protein-binding microcentrifuge tubes (1.5 mL)
• Calibrated micropipettes and sterile tips
• Analytical balance (if gravimetric verification is required)
• Dry ice or ice bucket for sample handling
• 0.22 µm sterile syringe filters (if sterile-filtered solution is needed for cell-based assays)

Note: All materials in contact with the peptide solution should be low-binding to minimize adsorption losses, which can be significant for small peptides at low concentrations.

Reconstitution Procedure

Follow these steps to reconstitute Enterostatin human (E118905) for experimental use:

1. Equilibrate to room temperature: Allow the vial to equilibrate to room temperature for 10–15 minutes before opening to prevent condensation from introducing moisture into the lyophilized material.
2. Centrifuge the vial: Briefly centrifuge the closed vial (1,000 × g, 30 seconds) to consolidate any powder that may have migrated to the cap during shipping.
3. Prepare the reconstitution solvent: Use sterile water or PBS (pH 7.4) as the primary solvent. The APGPR sequence is hydrophilic and is generally freely soluble in aqueous buffers.
4. Add solvent slowly: Pipette the appropriate volume of solvent along the inner wall of the vial to achieve the desired stock concentration (a stock of 1 mg/mL is recommended for flexibility). Do not vortex vigorously.
5. Mix gently: Rotate or gently pipette the solution up and down until the peptide is fully dissolved. If the solution appears turbid, incubate at room temperature for an additional 5 minutes and mix again.
6. Sterile filtration (optional): For cell-based assays, pass the solution through a 0.22 µm low-protein-binding syringe filter into a sterile collection tube.
7. Aliquot for storage: Prepare single-use aliquots to avoid repeated freeze-thaw cycles, which can degrade peptide integrity over time.

Important: Record the date of reconstitution on each aliquot tube. Reconstituted peptide should be used within the timeframe recommended under Storage Conditions below.

Storage Conditions and Stability

Lyophilized (as supplied): Store at −20 °C in a desiccated environment, protected from light and moisture. Under these conditions, the lyophilized peptide is expected to be stable for at least 12 months from the date of manufacture when stored properly.

Reconstituted solution: Store aliquots at −20 °C. Reconstituted Enterostatin human solutions are recommended for use within 3 months. For short-term use (within 1 week), aliquots may be stored at 4 °C.

General peptide stability considerations:

• Avoid repeated freeze-thaw cycles; each cycle may contribute to peptide bond hydrolysis and oxidation.
• Minimize exposure to ambient light, particularly if the working solution is dilute.
• Small pentapeptides such as APGPR can adsorb to standard polypropylene and polystyrene surfaces at very low concentrations; use low-binding tubes and plate coatings where applicable.
• Working solutions should be prepared fresh from stock on the day of the experiment whenever possible.

Experimental Applications and Dosing Guidance

Enterostatin human (APGPR, E118905) is used in research applications investigating the regulation of dietary fat consumption, satiety signaling pathways, and energy homeostasis. Common experimental contexts include:

• In vitro receptor binding and signaling assays: Used to investigate binding interactions and downstream signaling pathways associated with enterostatin activity.
• Cell-based functional assays: Applied to cell lines at concentrations determined by the specific assay system; researchers should perform dose-response experiments to establish appropriate working concentrations for their model.
• In vivo administration studies: Enterostatin has been investigated via peripheral and central administration routes in animal models of food intake regulation. Specific doses and routes should be established based on published literature relevant to the experimental model used.

Important dosing note: Specific working concentrations vary widely depending on the assay format, cell type, and experimental objective. Aladdin Scientific recommends that researchers consult the relevant primary literature and perform pilot dose-response experiments before committing to large-scale studies.

Quality check: Before use, visually inspect the reconstituted solution for particulates or unusual coloration. A colorless, clear solution is expected for APGPR at typical working concentrations.

Safety and Handling Precautions

Although Enterostatin human (APGPR) is a short synthetic peptide and is not classified as a hazardous substance under standard laboratory regulations, standard good laboratory practice (GLP) should be followed at all times:

• Wear appropriate personal protective equipment (PPE): laboratory coat, nitrile gloves, and safety glasses.
• Handle lyophilized peptide in a low-humidity environment or within a biosafety cabinet to prevent inhalation of fine powder and to protect the material from moisture uptake.
• Dispose of peptide-containing waste in accordance with your institution's chemical waste disposal policy.
• Consult the Safety Data Sheet (SDS) provided by Aladdin Scientific for full hazard and disposal information specific to this product (E118905).
• This product is intended FOR RESEARCH USE ONLY and is not suitable for diagnostic, therapeutic, or veterinary use.

Frequently asked questions

What solvent is recommended for reconstituting Enterostatin human (E118905)?

Sterile water for injection or phosphate-buffered saline (PBS, pH 7.4) is recommended as the primary reconstitution solvent. The Ala-Pro-Gly-Pro-Arg sequence is hydrophilic and dissolves readily in aqueous buffers. Avoid organic solvents unless specifically required by your assay format.

How should reconstituted Enterostatin human be stored, and for how long?

Reconstituted aliquots should be stored at −20 °C and are recommended for use within 3 months. For short-term use within one week, storage at 4 °C is acceptable. Always avoid repeated freeze-thaw cycles by preparing single-use aliquots prior to freezing.

What is the biological significance of the Ala-Pro-Gly-Pro-Arg sequence?

The APGPR pentapeptide is the human form of enterostatin, generated by tryptic cleavage of the N-terminal activation peptide of procolipase during pancreatic secretion. It has been studied extensively as a signaling peptide involved in the selective suppression of dietary fat intake and satiety regulation in research models. Its specific receptor interactions and downstream mechanisms remain an active area of investigation.

Can Enterostatin human (E118905) be used in cell-based assays?

Yes, Enterostatin human can be applied in cell-based assays. For such applications, it is recommended to sterile-filter the reconstituted solution through a 0.22 µm low-protein-binding syringe filter before use. Working concentrations should be optimized empirically for each cell line and assay format, as appropriate concentrations vary with experimental conditions.

How can peptide adsorption losses be minimized during experiments?

Use low-protein-binding microcentrifuge tubes, pipette tips, and multiwell plates throughout the experiment. Prepare working solutions at higher concentrations when feasible and dilute immediately before use. Avoid prolonged storage of dilute peptide solutions in standard polypropylene or polystyrene containers.

References

1. Erlanson-Albertsson C, York D. Enterostatin — a peptide regulating fat intake. Obes Res. 1997;5(4):360–372.
2. Erlanson-Albertsson C. The role of enterostatin in the regulation of food intake. Physiol Behav. 1992;52(5):953–958.
3. Liddle RA. Enterostatin: a potential mediator of fat-induced satiety. Proc Soc Exp Biol Med. 1995;210(3):191–196.

Products are supplied for research and development use only. Not for use in humans, animals, diagnosis, or therapy.