Description

Terminal Deoxynucleotidyl Transferase (TdT) is a specialized DNA polymerase enzyme that catalyzes the template-independent addition of deoxynucleotides to the 3'-hydroxyl terminus of DNA molecules. This unique property makes it an indispensable tool in molecular biology for modifying DNA ends. It is a critical reagent for researchers and developers in the biotechnology, pharmaceutical, and diagnostic sectors. Its primary applications include DNA labeling, homopolymer tailing, and the creation of diverse nucleic acid libraries.

Application

• TUNEL Assay (Terminal deoxynucleotidyl transferase dUTP Nick End Labeling): A cornerstone technique for the detection of DNA fragmentation and apoptosis (programmed cell death) in cells.
• DNA End-Labeling: For radioisotopic or fluorescent tagging of DNA fragments, essential for probes used in blotting and in situ hybridization.
• Homopolymer Tailing: Adding poly(A) or poly(dA) tails to cDNA or other DNA molecules to facilitate cloning strategies.
• Next-Generation Sequencing (NGS) Library Preparation: Used in certain protocols for adapter ligation and amplification of DNA libraries.
• Site-Directed Mutagenesis: Assisting in the introduction of specific mutations or sequences at DNA termini.
• Diagnostic Kit Manufacturing: A key enzyme component in commercial kits for apoptosis detection and genetic analysis.
• Antibody Diversity Research: Studying the mechanism of V(D)J recombination in the immune system, where TdT adds non-templated nucleotides.

Basic Information

Item	Detail
Product Name	Terminal Deoxynucleotidyl Transferase
CAS No.	9027-67-2
Molecular Formula	N/A (Protein/Enzyme)
Molecular Weight	Approx. 58-60 kDa (Calf Thymus)
Synonyms	Terminal Transferase; TdT; DNA Nucleotidylexotransferase; Deoxynucleotidyl Terminal Transferase; Terminal Adding Enzyme; EC 2.7.7.31; Nucleoside-triphosphate:DNA deoxynucleotidylexotransferase
EINECS	Contact for details

Quality Control

Our Terminal Deoxynucleotidyl Transferase is produced and tested under stringent quality management systems. Each lot is subjected to rigorous analytical testing to ensure high specific activity, purity, and the absence of contaminating nucleases. A comprehensive Certificate of Analysis (COA) detailing purity (by SDS-PAGE), specific activity (units/mg), and functional performance in standard assays is provided with every shipment to guarantee batch-to-batch consistency for your critical research and production needs.

Storage

Preserve in a tightly closed container, protected from light. For long-term stability, store at -20°C or below in a non-frost-free freezer. The enzyme is supplied in a buffered glycerol solution. Avoid repeated freeze-thaw cycles. Aliquot upon receipt for optimal performance. The product is hygroscopic (moisture-sensitive).

Specification

Item	Specification
Appearance	Clear, colorless solution
Identification (Activity)	Functional in standard tailing/labeling assay
Specific Activity	>15,000 units/mg protein
Purity (SDS-PAGE)	>95%
Contaminating Nucleases	Not detected
Endotoxin Level	<1.0 EU/μg (for relevant grades)
Storage Buffer	200 mM potassium phosphate, 1 mM DTT, 0.2% Triton X-100, 50% glycerol, pH 7.2

Note: Specifications can be tailored. Please contact us for the detailed technical data sheet of a specific grade.