Hanker-Yates Reagent (PPD-PC) is a premixed chromogen containing p-phenylenediamine dihydrochloride and catechol (pyrocatechol) for demonstrating horseradish peroxidase (HRP) activity in immunoperoxidase and histochemical workflows.
Composition: p-Phenylenediamine dihydrochloride and catechol (1,2-benzenediol; pyrocatechol).
In the presence of hydrogen peroxide, oxidative coupling of the reagent components produces an insoluble, osmiophilic reaction product suitable for localization of HRP activity. The developed reaction product is blue and can be used as an alternative chromogen to DAB in established HRP histochemistry procedures.
Hanker-Yates Reagent is used in HRP tracer visualization, cell biology, and neuroanatomical histochemistry, including procedures involving cryostat and free-floating tissue sections.
Key Properties
- Chromogen reagent for horseradish peroxidase (HRP) demonstration
- Contains p-phenylenediamine dihydrochloride and catechol (pyrocatechol)
- Produces a blue, insoluble reaction product
- Reaction product is osmiophilic for histochemical processing
- Used as an alternative chromogen to DAB in HRP workflows
- Catalog 08661; available as 5 × 1 g ampoules
Applications
Immunoperoxidase Histochemistry
Hanker-Yates Reagent is used as a chromogenic substrate system for visualization of HRP activity in immunoperoxidase staining procedures.
HRP Tracer Visualization
The reagent may be used to localize exogenous horseradish peroxidase tracer through formation of an insoluble reaction product at sites of enzyme activity.
Neuroanatomical Histochemistry
Hanker-Yates chemistry is used in HRP-based axonal transport and neuroanatomical studies involving fixed tissue and free-floating sections.
DAB-Alternative Chromogen Workflows
The p-phenylenediamine/catechol reaction provides an alternative chromogenic chemistry to diaminobenzidine for established HRP histochemistry methods.
Compatibility & Bonding Considerations
- Designed for HRP reactions performed in the presence of hydrogen peroxide
- A typical reaction medium uses 0.1 M Tris buffer at pH 7.6
- The developed reaction product is insoluble and osmiophilic
- Incubation conditions should remain consistent when comparing staining between samples
Reaction rate and staining intensity depend on reagent concentration, hydrogen peroxide concentration, buffer conditions, incubation time, tissue preparation, and HRP activity. Optimize and validate conditions for the specific staining or tracer protocol being used.
Application Tips
- Prepare the Hanker-Yates reaction medium immediately before use
- A typical preparation uses 7.5–15 mg of reagent per 10 ml of 0.1 M Tris buffer, pH 7.6, with 0.1 ml of 1% hydrogen peroxide
- Maintain consistent buffer pH, hydrogen peroxide concentration, and incubation time between samples
- Incubation times may be shorter than those used with DAB, depending on the procedure
Handling & Storage
- Store at 4°C in a cool, well-ventilated location
- Keep the container tightly closed when not in use
- Handle with good laboratory ventilation or in a chemical fume hood
- Wear protective gloves, safety glasses, and suitable protective clothing
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FAQ
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1. What is Hanker-Yates Reagent used for?
Hanker-Yates Reagent is used as a chromogen for demonstrating horseradish peroxidase activity in immunoperoxidase and histochemical procedures. The reaction produces an insoluble blue deposit at sites of HRP activity.
2. What does Hanker-Yates Reagent contain?
It contains p-phenylenediamine dihydrochloride and catechol, also known as pyrocatechol or 1,2-benzenediol.
3. Is Hanker-Yates Reagent the same as DAB?
No. Hanker-Yates Reagent uses p-phenylenediamine/catechol chemistry and is an alternative chromogen to diaminobenzidine (DAB) for HRP visualization.
4. How is Hanker-Yates reaction medium prepared?
A typical preparation uses 7.5–15 mg of reagent in 10 ml of 0.1 M Tris buffer at pH 7.6 with 0.1 ml of 1% hydrogen peroxide. Prepare the reaction medium immediately before use and follow the validated procedure for the specimen and application.
5. How should Hanker-Yates Reagent be stored and packaged?
Store the reagent at 4°C. Catalog 08661 is available as 5 × 1 g ampoules.
Safety & Documentation
Use appropriate laboratory ventilation and personal protective equipment when handling Hanker-Yates Reagent. Refer to the product Safety Data Sheet (SDS) for complete handling, storage, exposure-control, and safety guidance.
