Description
Thymidine — Pyrimidine Deoxynucleoside for DNA / Cell Cycle Applications
Thymidine (aka 2′-deoxythymidine, dThd) is a key pyrimidine nucleoside composed of the base thymine linked to a deoxyribose sugar. It is an essential building block of DNA, pairing with adenine in the double helix. 
In research and molecular biology, thymidine is used in a variety of applications including cell synchronization (S phase arrest), DNA labeling / tracing, DNA repair assays, hybridoma culture media (HAT medium supplementation), and nucleotide metabolism studies. 
Key Specifications & Identity
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CAS Number: 50-89-5 
 
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Molecular Formula: C₁₀H₁₄N₂O₅ 
 
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Molecular Weight: 242.23 g/mol 
 
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Appearance / Form: White crystalline or powdered solid 
 
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Storage / Handling: Store at 4 °C in a dry container, protected from moisture and light 
 
Functional Highlights & Applications
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Cell synchronization / S phase arrest
Thymidine supplementation can block cells at the S phase of the cell cycle, a tool often used in cell cycle and DNA replication studies. 
 
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DNA labeling / radiolabeling / tracing
Thymidine (or labeled derivatives) is used in assays to monitor DNA synthesis or repair by incorporation into nascent strands.
 
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Hybridoma / HAT medium support
In hybridoma and monoclonal antibody production, thymidine is a component of HAT medium (Hypoxanthine–Aminopterin–Thymidine) to select for successfully fused cells. 
 
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Nucleotide metabolism / flux studies
It’s useful in exploring pathways of salvage vs de novo synthesis, DNA repair, or perturbing nucleotide pools.
 
Usage Notes & Tips
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Prepare fresh stocks (e.g. in sterile water or buffer), filter-sterilize if needed.
 
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Because high concentrations may affect cell viability or metabolism, titrate carefully.
 
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Use in combination with proper controls (e.g. no-thymidine, labeled vs unlabeled).
 
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Protect from light and moisture to maintain stability.
 
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Always consult the Certificate of Analysis (COA) to confirm purity, lot information, and handling instructions.