Thermostable EndoQ (Endonuclease Q)

Thermostable EndoQ (Endonuclease Q)

Cat. No.

Concentration

Size

SRE00032-1

1,000 units/ml

100 units

SRE00032-2

1,000 units/ml

500 units

Description

Thermostable Endonuclease Q (EndoQ) is a heat-resistant DNA repair enzyme derived from hyperthermophilic archaea. It specifically recognizes and cleaves DNA at damaged bases including uracil, hypoxanthine, xanthine, and abasic (AP) sites. EndoQ cleaves the phosphodiester backbone on the 5’ side of the lesion, generating a single-strand break with a 3’-hydroxyl and a 5’-phosphate end. Its exceptional thermostability makes it ideal for use in high-temperature reactions, thermophilic DNA repair studies, and workflows involving thermophilic polymerases.

Features

  • Broad Lesion Recognition – Detects uracil, hypoxanthine, xanthine, and AP sites.
  • Thermostable – Active at temperatures up to 90°C.
  • Works on dsDNA and ssDNA – Effective on diverse DNA structures.
  • High Purity – Free from nonspecific endonuclease and exonuclease contamination.
  • Ligation-Ready Ends – Produces 3’-OH and 5’-phosphate termini.

Applications

  • High-temperature DNA damage detection and mapping
  • Removal of uracil or deaminated base lesions in thermophilic PCR products
  • Thermophilic DNA repair studies in vitro
  • Damage-specific DNA cleavage prior to high-temperature amplification
  • Combined use with thermostable DNA glycosylases for expanded specificity

Unit Definition

One unit is defined as the amount of enzyme required to cleave 1 pmol of an oligonucleotide ssDNA containing a single deoxyxanthosine site in 1 hour at 65°C. 

Storage Temperature:

-20°C for optimal long-term stability

Storage Buffer:

25 mM Tris-HCl (pH 8.0), 150 mM NaCl, 0.5 mM DTT, 0.5 mM EDTA, 50% Glycerol

Specifications

  • Expression System: Escherichia coli
  • Theoretical Molecular Weight: ~40,000 Daltons
  • Concentration: 1,000 units/ml
  • Heat Inactivation: No
  • Activity: Cleaves at uracil, hypoxanthine, xanthine, and AP sites
  • Optimal Temperature: 70–80°C
  • Thermal Stability: Retains activity after 30 min at 90°C

Quality Control

Each lot undergoes comprehensive testing including:

  • Functional activity assays
  • Purity analysis by SDS-PAGE (>95%)
  • DNase and DNA contamination testing
  • Sterility verification

Datasheet

MSDS

Important Handling Notes:
  • Avoid repeated freeze-thaw of the enzyme.
  • Store at –20°C for long-term stability.
  • Thaw on ice before use
  • Maintains high activity across a wide temperature range (37–90°C).
  • Optimal for use with thermostable DNA polymerases in damage-specific amplification workflows.
  • Cleavage leaves termini compatible with ligation or polymerase extension.
  • Use with Mg²⁺ or Mn²⁺ cofactors for maximal activity.
  • Not active on undamaged DNA.
Frequently Asked Questions

Q1: Can Thermostable EndoQ be used during PCR?
A: It can be added to pre-amplification steps or integrated into hot-start protocols for lesion removal before extension by a thermostable polymerase.

Q2: What is the main advantage over mesophilic EndoQ?
A: Its high thermal stability allows reactions at ≥70°C, improving lesion accessibility and compatibility with thermophilic enzymes.

Q3: Does it work on single-stranded DNA?
A: Yes, it can cleave damaged bases in both ssDNA and dsDNA.

Troubleshooting

Problem: Low cleavage efficiency

    • Ensure reaction temperature is within optimal range (70–80°C).
    • Verify presence of recognized lesions.
    • Check Mg²⁺ or Mn²⁺

Problem: Non-specific cleavage

    • Reduce enzyme amount or reaction time.
    • Confirm DNA integrity—nicks or pre-existing damage may lead to apparent background.
Disclaimer

Research Applications Only
This product is intended for research use or further manufacturing purposes only. Not for diagnostic procedures or direct therapeutic applications.