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Enzyme Tags
Enzyme tags are widely used reporter systems for immunoassays including ELISA, Western blotting, immunohistochemistry, and protein-based molecular biology applications. Enzyme-conjugated detection reagents generate amplified signals through catalytic substrate turnover, providing excellent sensitivity for detecting low-abundance targets.
Two of the most common enzyme tags are horseradish peroxidase (HRP) and alkaline phosphatase (ALP).
Advantages of Enzyme Tag Systems
- Signal amplification through catalytic turnover
- Multiple detection modes: colorimetric, fluorescent, chemiluminescent
- Well-established protocols across research and diagnostic applications
- Stable conjugates with long shelf life
Available Enzyme Reporter Systems
Enzyme | Detection Modes | Key Advantages | Catalog |
|---|---|---|---|
| HRP (Horseradish Peroxidase) | Colorimetric, fluorescent, chemiluminescent | Smallest enzyme label (~44 kDa), fastest turnover, lowest non-specific binding | HRP Conjugates |
| ALP (Alkaline Phosphatase) | Colorimetric, fluorescent, chemiluminescent | High stability, excellent for amplified detection systems | ALP Conjugates |
Choosing Between HRP and ALP
Consideration | HRP | ALP |
|---|---|---|
Molecular weight | ~44 kDa | ~140 kDa |
Turnover rate | Higher | Lower |
Signal stability | Substrate-dependent | More stable end products |
Endogenous interference | Block with H₂O₂/azide | Block with levamisole |
Best for | Rapid detection, high sensitivity | Long incubations, membrane-based assays |
For most immunoassays, HRP is preferred due to smaller size, lower background, and faster signal generation. ALP excels in applications requiring stable signal development or where endogenous peroxidase activity is problematic.
This document (01.0206.251203r1) was last updated on Thu Feb 12 2026. All trademarks and registered trademarks mentioned herein are the property of their respective owners.