Applications of Terminal Deoxynucleotidyl Transferase Enzyme in Biomedicine and Biotechnology

Terminal deoxynucleotidyl transferase (TdT) is a template-independent DNA polymerase that belongs to the X family of DNA polymerases. It is distinguished by its unique ability to catalyze the addition of deoxynucleotides to the ۳'-hydroxyl end of DNA without requiring a template. TdT is a unique enzyme in the field of low-fidelity polymerases that is responsible for generating random genetic information essential for the effective functioning of the adaptive immune system of vertebrates. Beyond its physiological importance, TdT has emerged as a pivotal enzyme in biomedicine and biotechnology due to its diverse applications in diagnostics, therapeutic development, and advanced molecular techniques. Clinically, TdT serves as a diagnostic biomarker for hematological malignancies, particularly acute lymphoblastic leukemia (ALL), where its overexpression aids in disease classification and prognosis assessment. Its role in detecting apoptosis through the TUNEL assay has significantly advanced cancer research by enabling precise identification of programmed cell death. In biotechnology, TdT’s versatility extends to DNA labeling, aptamer development, and enzymatic oligonucleotide synthesis, addressing key challenges in molecular assembly and precision engineering. Recent innovations have further broadened its utility, including fundamental contributions to the fabrication of DNA nanostructures, the development of DNA-based data storage systems, and enhancements in biosensor technologies for pathogen detection and molecular recognition. Despite its extensive applications, optimizing TdT's catalytic efficiency, substrate specificity, and stability remains a challenge for industrial and clinical use. However, various TdT engineering and hybrid technologies—such as TdT-CRISPR systems and TdT nanoparticle platforms—offer significant promise in overcoming these limitations. This review provides a comprehensive analysis of the biochemical properties, underlying mechanisms, and wide-ranging applications of TdT in biomedicine and biotechnology. It examines the enzyme's physiological role in adaptive immunity, its diagnostic relevance in hematological malignancies, and its versatile applications in DNA synthesis, labeling, nanotechnology, biosensors, and emerging fields like molecular data storage and aptamer development. Furthermore, the review highlights recent advancements in TdT engineering and hybrid technologies while addressing challenges related to substrate specificity and catalytic optimization.

کلیدواژه ها:

terminal deoxynucleotidyl transferase ، biomedicine ، biotechnology ، cancer diagnostics ، DNA nanotechnology ، oligonucleotide synthesis