Pepsin Antigen Retrieval Solution - BioReagent,for microscopy,Suitable for Immunohistochemistry(IHC)

Cat. No.: G1508982

CALIDAD & PUREZA BioReagent, for Microscopy, Suitable for Immunohistochemistry(IHC)

Storage

Store at -20°C

Shipped In

Ice chest + Ice pads

Application

Cell Staining, IHC

Descripción general

During tissue preparation, antigens are masked by the effects of chemical reagents, and the peptide chains of some antigens become distorted due to heating. As a result, these antigens cannot be visualized during immunohistochemical staining. To address these issues, the process of re-exposing or restoring these antigens using chemical reagents and heat is called antigen retrieval. Buffers such as citrate, EDTA, or Tris can re-expose antigens masked by formalin under heating conditions without damaging antigenic epitopes, thereby improving antigen detection rates, reducing background staining, and enhancing diagnostic accuracy.

Before the advent of heat-induced antigen retrieval, epitope retrieval induced by enzymes such as trypsin, proteinase K and pepsin was the most commonly used method. This pepsin antigen retrieval solution is mainly prepared by dissolving pepsin in a dilute acid solution. It can expose antigenic epitopes in samples such as paraffin sections, thereby significantly improving the immunostaining effect. Paraffin sections generally require antigen retrieval treatment, while frozen sections do not necessarily need such treatment. Antigen retrieval can enhance the immunostaining effect of paraffin sections and also improve that of frozen sections to varying degrees; antigen retrieval may be considered when the immunostaining effect of frozen sections is unsatisfactory. Based on the calculation of 10 ml of 1× antigen retrieval solution required per slide, 100 ml of the solution can be used for the antigen retrieval of 10 samples. This reagent is for research use only and not intended for clinical diagnosis or any other applications.

Materials to Be Prepared by Users

1. Graded ethanol solutions

2. Double-distilled water or deionized water

3. Heating equipment

4. Immunostaining wash buffer

Operating Procedures (For Reference Only)

(1) Paraffin Sections

1. Deparaffinization and Rehydration

① Deparaffinize sections with xylene or deparaffinization clearing solution for 3 times, 3-5 minutes each time.

② Dehydrate with anhydrous ethanol for 2 times, 3-5 minutes each time.

③ Treat with 95% ethanol for 3-5 minutes.

④ Treat with 90% ethanol for 3-5 minutes.

⑤ Treat with 80% ethanol for 3-5 minutes.

⑥ Treat with 70% ethanol for 3-5 minutes.

⑦ Rinse with distilled water for 2 times, 3-5 minutes each time.

2. Antigen retrieval: Immerse the sections in pepsin antigen retrieval solution and incubate at 37 ℃ for 10-25 min.

3. Rinse with immunostaining wash buffer or tap water for 1-2 times, 3-5 min each time, and rinse thoroughly.

4. Perform the subsequent immunostaining steps.

(2) Frozen Sections

1. Rinse the sections with immunostaining wash buffer or tap water for 5 min.

2. Antigen retrieval: Immerse the sections in pepsin antigen retrieval solution and incubate at 37 ℃ for 10-25 min.

3. Rinse with immunostaining wash buffer or tap water for 1-2 times, 3-5 min each time, and rinse thoroughly.

4. Perform the subsequent immunostaining steps.

(3) Other Samples

Operate on other samples with reference to the procedures for paraffin sections or frozen sections.

Precautions

1. Allow the pepsin antigen retrieval solution to return to room temperature before use, and avoid repeated freeze-thaw cycles.

2. When immersing sections in the pepsin antigen retrieval solution, the optimal incubation time should be determined experimentally according to different samples and target proteins.

3. For your safety and health, wear a lab coat and disposable gloves during operation.

4. Use the reagent as soon as possible after opening to prevent adverse effects on subsequent experimental results.

Especificaciones

Especificaciones y pureza

BioReagent,for microscopy,Suitable for Immunohistochemistry(IHC)

Estabilidad y almacenamiento

Store at -20℃ long term (12 months).

Condiciones de almacenamiento de almacenamiento

Store at -20°C

Enviado en

Ice chest + Ice pads

Este producto requiere envío en cadena de frío. Los servicios terrestres y otros servicios económicos no están disponibles.

Grado

BioReagent, for Microscopy, Suitable for Immunohistochemistry(IHC)

Product Line

Productos biológicos

Application Protocols

Item-specific details

• The manufacturer has not provided a specific protocol for this item. The following is general literature guidance for pepsin-based antigen retrieval in IHC; optimize for your tissue and antibody.

General IHC antigen retrieval with pepsin (literature protocol)

1. Section prep: Bake slides if required, then deparaffinize in xylene (2×5–10 min) and rehydrate through graded ethanol to distilled water.
2. Optional quench: Treat with 0.3% H2O2 in methanol or buffer to quench endogenous peroxidase if using HRP detection; rinse well.
3. Retrieval: Cover sections with Pepsin Antigen Retrieval Solution ensuring complete coverage. Incubate at ambient to 37–42°C for 5–20 min initially.
4. Monitor: Inspect one test slide microscopically to assess morphology and antigen signal (pilot stain), adjusting time as needed (up to ~30 min if required).
5. Stop and wash: Rinse slides in PBS or TBS (3×5 min) to remove enzyme and halt digestion.
6. Blocking: Apply serum/protein block appropriate to your detection system; proceed with primary antibody incubation per datasheet.
7. Detection: Perform secondary and detection steps (chromogenic or fluorescent) as validated.
8. Counterstain and mount: Counterstain (e.g., hematoxylin), dehydrate if chromogenic IHC, and mount.

Notes

• Validate for each antibody/tissue pairing. Include positive/negative controls. Avoid over-digestion to preserve tissue morphology.

Biological Roles

General biochemistry (literature)

• Pepsin is a stomach-derived aspartic endopeptidase involved in protein digestion, produced as pepsinogen and activated in acidic environments. It preferentially cleaves peptide bonds adjacent to aromatic amino acids.
• In histology/IHC workflows, exogenous pepsin is repurposed for controlled extracellular and intracellular proteolysis in fixed tissues to unmask epitopes masked by formaldehyde crosslinks.
• Substrate scope: denatured and crosslinked proteins present in FFPE sections; activity is influenced by pH, ionic strength, temperature, and incubation time.
• Enzyme stability: Active at acidic pH; rapidly loses activity with prolonged exposure to neutral/alkaline pH or elevated temperatures without stabilizers.

Item-specific note

• This product provides pepsin activity within an aqueous medium appropriate for microscopy workflows; exact composition and activity are not specified for this item and should be confirmed on the CoA/Spec Sheet.

Buffer Applications

Applicability to this product

• This product is an antigen retrieval solution rather than a buffering system intended to maintain a defined pH range during biochemical assays.

General guidance (literature)

• Following retrieval, rinse slides with a suitable buffer (e.g., PBS or TBS) and conduct blocking and antibody incubations in buffers optimized for your detection chemistry. Typical pH ranges: PBS ~7.2–7.6; TBS ~7.4–8.0.
• If subsequent enzymatic detection systems are used (e.g., HRP), ensure buffer components are compatible with the enzyme and chromogen system.

Item-specific buffer specifications (pH, composition)

• Not specified for this item; refer to CoA/Spec Sheet.

Green Alternatives

Context

• Environmental considerations center on process conditions and waste minimization rather than replacing the aqueous solution per se.

Alternative retrieval strategies (literature; not product specifications)

• Heat-Induced Epitope Retrieval (HIER) buffers (e.g., citrate pH ~6, Tris-EDTA pH ~9) avoid proteolytic enzymes and can be performed in pressure cookers, microwaves, or water baths, generating predominantly aqueous buffer waste.
• Enzyme alternatives (e.g., proteinase K, trypsin) may offer different specificity profiles that require shorter times or milder conditions, potentially reducing reagent consumption.

Comparison (general)

• Pepsin EIER: Lower temperature, enzymatic specificity; risk of over-digestion and variable activity; good for heat-labile epitopes.
• HIER (citrate/EDTA): No enzymes, consistent across lots; may require high energy/temperature and can damage morphology if overdone.
• Decision factors: antigen nature, fixation history, morphology sensitivity, lab equipment/energy use, and operator safety.

Greener practice tips

• Right-size batch volumes to minimize excess solution.
• Reuse retrieval baths only if validated for performance and contamination control; otherwise, prepare minimal fresh volumes.
• Dispose of protein-containing aqueous waste per institutional guidelines; avoid unnecessary additives that complicate wastewater treatment.

Pharmaceutical Uses

Applicability

• This product is supplied for research use only and is intended for microscopy/IHC workflows. It is not formulated or qualified as a pharmaceutical excipient or active ingredient.

General context (literature)

• Enzymes like pepsin are used industrially and pharmaceutically as processing aids and in diagnostics; however, any such use requires dedicated grades, regulatory compliance, and detailed specifications not provided here.

Item-specific note

• Research Use Only (RUO) per Product Data; no pharmacopeial status or compliance claims are made for this item.

Physical Properties

Item-specific facts (from Product Data)

• Physical state/appearance: Not specified for this item; refer to CoA/Spec Sheet.
• Concentration, pH, ionic strength: Not specified for this item; refer to CoA/Spec Sheet.
• Density, refractive index, osmolality: Not specified for this item; refer to CoA/Spec Sheet.

General/literature values and context (not specifications)

• Pepsin exhibits maximal catalytic activity in strongly acidic media (literature optimum pH ~1–3) and is rapidly inactivated above neutral pH or at elevated temperature when not stabilized.
• Typical pepsin antigen-retrieval working solutions reported in protocols are aqueous and acidic; many labs employ temperatures from ambient to ~37–42°C during incubation to balance epitope exposure with tissue preservation (parameters are assay- and tissue-dependent).
• Boiling points, melting points, and logP are not applicable to aqueous formulated enzyme solutions. For this product, specific physicochemical attributes should be taken from the CoA/SDS when available.

Quality and Grades

Item-specific facts (from Product Data)

• Grade: BioReagent, for Microscopy; Suitable for Immunohistochemistry (IHC).

Interpretation and implications

• BioReagent grade indicates the product is intended for laboratory biological applications with controlled impurity profiles and performance appropriate for routine research workflows.
• “For Microscopy” emphasizes low background and compatibility with histological staining on glass slides, including FFPE tissue sections.
• “Suitable for IHC” signifies functional utility in antigen retrieval workflows upstream of antibody staining, supporting reliable epitope exposure with minimal tissue damage when used under optimized conditions.

What is NOT specified for this item

• Exact enzyme activity units, concentration, stabilizers, pH, and preservative content: Not specified for this item; refer to CoA/Spec Sheet.

Practical quality notes (general)

• For reproducible IHC, lot-to-lot verification (slide controls) is recommended. Record incubation time and temperature specific to each lot if the activity varies.
• Low particulate and low autofluorescence matrices are preferred for microscopy; ensure glassware and wash buffers are clean to prevent background.
• If using for fluorescence IHC/IF, confirm absence of intrinsic fluorescence from excipients; if uncertain, run a no-primary control.

Reaction and Applications

Item-specific use (from Product Data)

• Application: Antigen retrieval for immunohistochemistry (IHC) in microscopy workflows.

Mechanistic context (literature)

• Formalin fixation creates methylene bridges and other crosslinks that can sterically hinder epitopes. Pepsin-mediated retrieval employs proteolysis to cleave crosslinked or denatured protein regions, restoring epitope accessibility, particularly for antigens unresponsive to heat-induced epitope retrieval (HIER).

When to choose pepsin retrieval (general guidance)

• Useful for heavily crosslinked tissues (e.g., long-fixed FFPE), extracellular matrix-rich samples, and specific epitopes that are conformationally masked by fixation or resistant to HIER.
• Often preferred for membrane or nuclear antigens that lose antigenicity upon high-temperature HIER, or where heat damages morphology.

Practical tips

• Optimize three parameters: enzyme concentration (as supplied), temperature (often ambient to ~37–42°C), and time (commonly 5–30 min). Start with conservative conditions to avoid over-digestion.
• Monitor tissue morphology under a microscope during method development; adjust incubation to balance signal intensity and structural preservation.
• Stop reaction with immediate thorough buffer washes and proceed to blocking to reduce nonspecific binding.
• Validate with positive/negative control tissues and a no-retrieval control to confirm retrieval benefit.
• Note that some carbohydrate-rich epitopes or delicate structures may be sensitive to proteolysis; consider HIER or milder proteases if needed.

Reaction Conditions

Item-specific conditions

• Exact working conditions (time, temperature, pH, enzyme activity) are not specified for this item; refer to CoA/Spec Sheet and SDS.

General IHC antigen retrieval conditions with pepsin (literature; for method development only)

• Temperature: Often ambient to 37–42°C to balance retrieval efficiency with morphology preservation.
• Time: Commonly 5–30 minutes; start short (e.g., 5–10 min) and titrate upward as needed.
• Pre-treatment: Deparaffinize FFPE sections thoroughly and rehydrate through graded alcohols to water before retrieval.
• Post-treatment: Rinse immediately with copious buffer (PBS/TBS), then proceed to blocking.
• Controls: Include a no-retrieval slide and a known positive control tissue to benchmark improvement.
• Termination: Thorough washing effectively halts proteolytic activity; optional neutralization buffers may be used depending on downstream steps.

Compatibility notes

• Adhesive slides help maintain tissue integrity during proteolysis.
• Some antigens are sensitive to proteolysis; confirm specificity by testing reduced times or alternative retrieval (HIER) if signal diminishes with longer incubations.

Safety and Handling

Item-specific facts (from Product Data)

• GHS classification, signal word, H-statements, pictograms: Not specified for this item; refer to SDS.
• Storage condition: Store at -20°C. Shipped with ice chest + ice pads.

General safety guidance (literature/best practice; defer to SDS for authoritative information)

• Enzyme powders and solutions can cause allergic sensitization upon inhalation or skin contact; avoid aerosolization and splashes. Work in a well-ventilated area or biological safety cabinet when appropriate.
• Personal protective equipment: lab coat, nitrile gloves, and safety glasses; face shield if splash risk. Avoid breathing vapors/aerosols. Wash thoroughly after handling.
• Incompatibilities: Strong oxidizers and extremes of pH may denature proteins or degrade excipients. Avoid contamination with protease-sensitive reagents (e.g., protein-based blocking buffers) until after retrieval is complete and the slide is washed.
• First aid (overview): In case of skin/eye contact, rinse with water for at least 15 minutes; remove contaminated clothing. If inhaled, move to fresh air. If ingested, rinse mouth. Seek medical attention as needed. Always consult the product SDS for specific hazard and response guidance.
• Spill response: Absorb with inert material, avoid dust/aerosols, clean area with water and appropriate detergent. Decontaminate surfaces and dispose of waste per institutional guidelines.
• Special risks: Proteolytic activity—can digest proteins; protect skin/eyes and avoid prolonged contact with biological samples not intended for retrieval.

Solvent Selection

Applicability to this product

• This is an aqueous antigen retrieval solution supplied for direct use in tissue processing. Traditional “solvent selection” for organic synthesis does not apply.

Operational considerations (general)

• Compatibility: Aqueous and acidic conditions typical of pepsin-based retrieval are generally compatible with most glass slides and common tissue adhesives. Validate with specialized adhesives or membrane slides.
• Rinsing: Following retrieval, rinse thoroughly with PBS or Tris-buffered saline (TBS) according to your downstream antibody system. Choice of PBS vs TBS can affect certain antibody interactions (e.g., phosphate-sensitive systems).

Storage and Reconstitution

Item-specific facts (from Product Data)

• Storage condition: Store at -20°C.
• Shipping: Ice chest + ice pads.
• Reconstitution: Not specified for this item; refer to CoA/Spec Sheet.

General handling guidance (literature/best practice)

• If supplied frozen, thaw on ice. Mix gently by inversion; avoid vigorous vortexing to minimize foaming and enzyme denaturation.
• Aliquot upon first thaw to minimize freeze–thaw cycles. Typical practice is to limit to ≤3–5 freeze–thaw events; verify stability empirically.
• Short-term storage: Keep on ice during use. For interim storage (days to a week), 2–8°C may be acceptable, but follow the product’s CoA for definitive guidance.
• Avoid microbial contamination: Use sterile tools and keep container closed. Do not return used solution to the stock bottle.
• Light sensitivity: Not typically light sensitive, but store protected from light to preserve any light-labile excipients if present.
• Stability and expiry: Use before the labeled expiration date. For precise shelf-life after opening and working solution stability, consult the CoA/Spec Sheet.

Structure and Identity

Item-specific facts (from Product Data)

• Product: Pepsin Antigen Retrieval Solution (SKU: G1508982)
• Intended use: BioReagent for microscopy; suitable for immunohistochemistry (IHC)
• Format: Antigen retrieval solution (aqueous), enzyme-based (pepsin)
• Molecular formula: Not specified for this item; refer to CoA/Spec Sheet.
• Molecular weight: Not specified for this item; refer to CoA/Spec Sheet.
• SMILES / InChI / InChIKey / CAS / CID: Not specified for this item; refer to CoA/Spec Sheet.

General chemistry/biochemistry (literature)

• Pepsin is an aspartic endopeptidase (EC 3.4.23.1) that preferentially cleaves peptide bonds involving aromatic residues (Phe, Trp, Tyr) on the N-terminal side under acidic conditions.
• Antigen-retrieval solutions formulated with pepsin are typically buffered/acidified aqueous preparations that promote controlled proteolysis of formalin-induced crosslinks in FFPE tissues, exposing masked epitopes for antibody binding.
• Structural features (conceptual): large globular protein enzyme bearing two catalytic aspartates in a bilobal fold; antigen-retrieval “solution” contains this protein in an aqueous medium, potentially with stabilizers and salts (compositions vary by manufacturer; not specified for this item).

Synthetic Utility

Not typically applicable

• As an aqueous antigen retrieval solution for microscopy, this product is not used as a reagent in organic synthesis or small-molecule transformations.

Related laboratory utility (general)

• In histology, pepsin functions as a selective protease to modulate tissue protein architecture, conceptually analogous to “chemical deprotection” of epitopes. It has utility in method development for IHC/IF where proteolysis is required instead of or in addition to heat-induced epitope retrieval.

Target Specificity

Not applicable to this product

• This listing is an antigen retrieval solution (enzyme-based), not an antibody or affinity reagent. Therefore, it has no target antigen, clone, epitope, isotype, or species reactivity attributes. Use it upstream of antibody staining to improve epitope exposure for a wide range of targets, as empirically determined.

Preguntas frecuentes

What does for microscopy mean?

for microscopy indicates that the material has been processed and tested for specialty industrial processing. Specifications focus on the impurities that affect performance in that application — for example, metal content for electronics, particle size for batteries, refractive index for optics, or moisture content for moisture-sensitive processes.

What does BioReagent mean?

BioReagent indicates that the product has been processed and tested for biological and biochemical applications. Specifications may include endotoxin limits, microbial controls, sterility, low DNase/RNase/protease activity, and verified biological activity where relevant.

How should this product be stored?

Store at ?20 °C. Freezer storage is required to maintain the specified shelf life.

How is this product shipped?

This product ships in an insulated container with ice pads. Unpack on arrival and transfer it to the storage condition stated above.

What documentation is provided?

Available product documentation, including Certificates of Analysis (COA), Safety Data Sheets (SDS), and specification sheets, is shown in the product document area. Document availability and access follow the current site policy.