Target type: biologicalprocess
The directed movement of thymine, 5-methyluracil, into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. [GO:sl]
Thymine transport is a complex process that involves the movement of thymine, a pyrimidine base essential for DNA synthesis, across cellular membranes. This process is crucial for maintaining nucleotide pools within cells and ensuring proper DNA replication. The transport mechanism for thymine is highly regulated and involves a variety of proteins and enzymes. In bacteria, the primary transporter for thymine is the pyrimidine permease (PyrP). PyrP is a member of the major facilitator superfamily (MFS) of transporters and functions as a proton-symporter, meaning it couples the movement of thymine into the cell with the influx of protons. This mechanism is driven by the electrochemical gradient across the membrane. In eukaryotic cells, thymine transport is more intricate and involves a combination of passive diffusion and active transport mechanisms. Passive diffusion allows for the movement of thymine across the cell membrane down its concentration gradient, while active transport systems utilize energy to move thymine against its concentration gradient. The specific proteins responsible for active thymine transport in eukaryotes are not fully elucidated, but several candidate proteins have been identified. These proteins belong to the solute carrier (SLC) family, which encompasses a wide range of membrane transporters. Regulation of thymine transport is essential for maintaining cellular homeostasis and preventing imbalances in nucleotide levels. Factors such as the availability of thymine in the extracellular environment, the cellular demand for thymine for DNA synthesis, and the activity of specific enzymes involved in thymine metabolism can all influence the rate of thymine transport. Dysregulation of thymine transport can have severe consequences for cellular function, including impaired DNA replication and cell division. In summary, thymine transport is a crucial process for ensuring adequate supplies of thymine for DNA synthesis. The mechanisms involved vary between prokaryotes and eukaryotes, and the process is tightly regulated to maintain cellular homeostasis. '
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| Protein | Definition | Taxonomy |
|---|---|---|
| Equilibrative nucleoside transporter 1 | An equilibrative nucleoside transporter 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q99808] | Homo sapiens (human) |
| Equilibrative nucleoside transporter 2 | An equilibrative nucleoside transporter 2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q14542] | Homo sapiens (human) |
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| dilazep | dilazep : A member of the class of diazepanes that is 1,4-diazepane substituted by 3-[(3,4,5-trimethoxybenzoyl)oxy]propyl groups at positions 1 and 4. It is a potent adenosine uptake inhibitor that exhibits antiplatelet, antianginal and vasodilator properties. Dilazep: Coronary vasodilator with some antiarrhythmic activity. | benzoate ester; diazepane; diester; methoxybenzenes | cardioprotective agent; platelet aggregation inhibitor; vasodilator agent |
| dipyridamole | dipyridamole : A pyrimidopyrimidine that is 2,2',2'',2'''-(pyrimido[5,4-d]pyrimidine-2,6-diyldinitrilo)tetraethanol substituted by piperidin-1-yl groups at positions 4 and 8 respectively. A vasodilator agent, it inhibits the formation of blood clots. Dipyridamole: A phosphodiesterase inhibitor that blocks uptake and metabolism of adenosine by erythrocytes and vascular endothelial cells. Dipyridamole also potentiates the antiaggregating action of prostacyclin. (From AMA Drug Evaluations Annual, 1994, p752) | piperidines; pyrimidopyrimidine; tertiary amino compound; tetrol | adenosine phosphodiesterase inhibitor; EC 3.5.4.4 (adenosine deaminase) inhibitor; platelet aggregation inhibitor; vasodilator agent |
| lidoflazine | Lidoflazine: Coronary vasodilator with some antiarrhythmic action. | diarylmethane | |
| uridine | uridines | drug metabolite; fundamental metabolite; human metabolite | |
| phlorhizin | aryl beta-D-glucoside; dihydrochalcones; monosaccharide derivative | antioxidant; plant metabolite | |
| methylthioinosine | Methylthioinosine: 6-(Methylthio)-9-beta-D-ribofuranosylpurine. An analog of inosine with a methylthio group replacing the hydroxyl group in the 6-position. | purine ribonucleoside; thiopurine | |
| hyaluronoglucosaminidase | kinetin riboside: preferentially induces apoptosis by modulating Bcl-2 family proteins and caspase-3 in cancer cells; structure in first source | purine nucleoside | |
| gemcitabine | gemcitabine : A 2'-deoxycytidine having geminal fluoro substituents in the 2'-position. An inhibitor of ribonucleotide reductase, gemcitabine is used in the treatment of various carcinomas, particularly non-small cell lung cancer, pancreatic cancer, bladder cancer and breast cancer. | organofluorine compound; pyrimidine 2'-deoxyribonucleoside | antimetabolite; antineoplastic agent; antiviral drug; DNA synthesis inhibitor; EC 1.17.4.1 (ribonucleoside-diphosphate reductase) inhibitor; environmental contaminant; immunosuppressive agent; photosensitizing agent; prodrug; radiosensitizing agent; xenobiotic |
| draflazine | draflazine: a nucleoside transport inhibitor; has cardioprotective effect; draflazine is the (-)-enantiomer; R 88016 is the (+)-enantiomer | ||
| adenosine | quinquefolan B: isolated from roots of Panax quinquefolium L.; RN not in Chemline 10/87; RN from Toxlit | adenosines; purines D-ribonucleoside | analgesic; anti-arrhythmia drug; fundamental metabolite; human metabolite; vasodilator agent |
| 4-nitrobenzylthioinosine | 4-nitrobenzylthioinosine: inhibitor of nucleoside transport; acts on ENT1 | purine nucleoside | |
| n(6)-benzyladenosine | N(6)-benzyladenosine: RN given refers to parent cpd | ||
| 6-(4-nitrobenzylthio)guanosine | 6-(4-nitrobenzylthio)guanosine: inhibitor of nucleoside transport | ||
| 5-iodotubercidin | 7-iodotubercidin: inhibits Toxoplasma gondii adenosine kinase | organoiodine compound | |
| n(6)-phenyladenosine | purine nucleoside | ||
| tecadenoson | tecadenoson: an A1 adenosine receptor agonist | ||
| 2-hydroxy-5-nitrobenzylthioguanosine | |||
| n(6)-cyclopentyladenosine | |||
| 6-benzylthioinosine | 6-benzylthioinosine: a subversive substrate of T gondii adenosine kinase; structure in first source |