- Home
- IVD
- By Technology Types
- By Diseases Types
- By Product Types
- Research
- Resource
- Distributors
- Company
| Product Name | Terminal Deoxynucleotidyl Transferase (TdT), Recombinant, 20 U/µL |
| Catalog No. | IEC-HMM-0073 |
| Description | Recombinant terminal deoxynucleotidyl transferase (TdT), a template-independent DNA polymerase that catalyzes the addition of deoxynucleotides to the 3′-OH terminus of DNA molecules. TdT is essential for TUNEL apoptosis assays, 3′-end DNA labeling, homopolymer tailing for cloning, and next-generation sequencing adapter addition. Recombinant production ensures consistent activity and purity. |
| Intended Use | TUNEL assay for apoptosis detection; 3′-end labeling of DNA with modified nucleotides (biotin, digoxigenin, fluorophores); homopolymer tailing (dA or dT) for TA cloning; RACE (Rapid Amplification of cDNA Ends) cDNA tailing; NGS library adapter addition. |
| Principle / Technology | TdT adds deoxynucleoside triphosphates to 3′-OH termini of DNA in a template-independent manner; prefers single-stranded DNA with 3′ overhangs but also accepts blunt and recessed 3′ ends (with lower efficiency); Co²⁺ is the preferred divalent cation cofactor (Mg²⁺ and Mn²⁺ also functional) |
| Detection Method | For 3′-end labeling: mix DNA, modified dNTP, 1× TdT buffer, CoCl₂, and TdT enzyme; incubate 37 °C for 30-60 min; stop by heating 70 °C 10 min or EDTA addition; for TUNEL: combine with labeled-dUTP for incorporation at DNA strand breaks |
| Sample Type | Linear dsDNA, ssDNA, oligonucleotides with free 3′-OH termini; DNA with 3′-phosphate, 3′-biotin, or 3′-ddNTP modifications are NOT substrates |
| Sensitivity / LOD | Adds 10-100 nucleotides per 3′-end in 30 min depending on dNTP:dNTP ratio and DNA end structure; detects picomole quantities of DNA 3′-ends |
| Reaction Conditions / Protocol | Reaction: 37 °C for 30-60 min in 1× TdT buffer with 1 mM CoCl₂ or 5 mM MgCl₂; CoCl₂ provides 5-10× higher activity than Mg²⁺; typical reaction volume 20-50 µL with 5-20 U TdT |
| Components / Formulation | TdT Enzyme (20 U/µL), 5× TdT Buffer (500 mM potassium cacodylate pH 7.2, 5 mM CoCl₂), 25 mM CoCl₂ supplement solution |
| Storage Conditions | -20 °C; enzyme in 50% glycerol — does not freeze solid; CoCl₂ solution store at 4 °C to prevent precipitation |
| Shelf Life | 24 months at -20 °C; CoCl₂ 12 months at 4 °C |
| Package Specifications | 500 U, 2,500 U, 10,000 U |
| Product Form | Liquid enzyme in 50% glycerol storage buffer |
| Key Features | Recombinant — consistent activity; optimal with Co²⁺ cofactor (10× activity boost); adds all four dNTPs, modified dNTPs, and ddNTPs; essential for TUNEL apoptosis detection; template-independent reaction simplifies experimental design |
| Purity | Recombinant >99% SDS-PAGE; no detectable exonuclease, endonuclease, or phosphatase activity; endotoxin <0.1 EU/U |
| Concentration | 20 U/µL; 1 U = incorporation of 1 nmol dATP into acid-insoluble form in 60 min at 37 °C using d(pT)₆ as primer |
| Activity / Unit Definition | 20,000 U/mL |
| Molecular Weight | ~60 kDa (bovine TdT); recombinant form molecular weight similar |
| Source / Origin | Recombinant bovine TdT expressed in E. coli; functionally identical to calf thymus TdT |
| pH Range / Optimal pH | pH 7.5–8.5 for polymerase activity; pH 7.5–8.0 for ligation; pH 7.5–8.0 for transcription |
| Shipping Conditions | Cold pack -20 °C |
| Expiration Date / Stability | 24 months at -20 °C; avoid repeated freeze-thaw; CoCl₂ solution — discard if dark precipitate forms |
| Regulatory / Compliance | For laboratory and research use only; RUO; potassium cacodylate contains arsenic — handle with gloves; ISO 9001 |
| Compatibility | Compatible with all dNTPs (dATP, dCTP, dGTP, dTTP), modified dNTPs (biotin-, digoxigenin-, fluorescein-dUTP), and dideoxy NTPs; ribonucleotides (NTPs) are poor substrates — use poly(A) polymerase for RNA tailing; Co²⁺ provides highest activity; for Co²⁺-sensitive downstream applications, use Mg²⁺ (5 mM) or Mn²⁺ (1 mM) |
| Recommended Buffer System | Tris-HCl, KCl, MgCl₂-based buffers; glycerol-containing storage buffers |
| Application Notes / Precautions | Aliquot enzymes to avoid repeated freeze-thaw; use dedicated nuclease-free workspace; verify enzyme activity for critical applications |
| Batch-to-Batch Consistency | Enzyme specific activity within ±15% of reference lot; functional testing per lot |
For research use only, not for clinical use.
|
There is no product in your cart. |
Copyright © 2026 Alta DiagnoTech. All rights reserved.
