Target type: biologicalprocess
The directed movement of a nucleobase, any nitrogenous base that is a constituent of a nucleoside, nucleotide, or nucleic acid, into, out of or within a cell, or between cells, by means of some agent such as a transporter or pore. [ISBN:0198506732]
Nucleobase transport is a crucial process in cellular metabolism, ensuring the delivery of essential building blocks for nucleic acid synthesis, DNA replication, and repair. The process involves the movement of nucleobases, the fundamental units of DNA and RNA, across cellular membranes. These membranes act as barriers, selectively allowing certain molecules to pass while preventing others.
The transport of nucleobases is facilitated by specialized membrane proteins called nucleobase transporters. These proteins exhibit remarkable specificity, recognizing and binding to specific nucleobases, such as adenine, guanine, cytosine, thymine, and uracil. This selective binding ensures that only the appropriate nucleobases are transported across the membrane.
The transport mechanisms can be broadly categorized as active or passive:
1. Active transport: This process requires energy to move nucleobases against their concentration gradient, from an area of low concentration to an area of high concentration. This energy is typically derived from ATP hydrolysis. Active transport systems often play a critical role in maintaining intracellular levels of specific nucleobases, essential for proper cellular function.
2. Passive transport: This process does not require energy and relies on the concentration gradient of the nucleobase. Nucleobases move from a region of high concentration to a region of low concentration, facilitated by membrane proteins that act as channels or carriers. This type of transport is particularly important for the uptake of nucleobases from the extracellular environment or the movement of nucleobases between cellular compartments.
Nucleobase transport is tightly regulated, ensuring that cells have an appropriate supply of nucleobases for their metabolic needs. Dysregulation of nucleobase transport can have severe consequences for cellular health, contributing to diseases such as cancer and genetic disorders. Understanding the intricate mechanisms of nucleobase transport is critical for developing novel therapeutic strategies targeting these vital processes.'
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| Protein | Definition | Taxonomy |
|---|---|---|
| Solute carrier family 23 member 1 | A solute carrier family 23 member 1 that is encoded in the genome of human. [PRO:DNx, UniProtKB:Q9UHI7] | Homo sapiens (human) |
| 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 | ||
| ascorbic acid | Ascorbic Acid: A six carbon compound related to glucose. It is found naturally in citrus fruits and many vegetables. Ascorbic acid is an essential nutrient in human diets, and necessary to maintain connective tissue and bone. Its biologically active form, vitamin C, functions as a reducing agent and coenzyme in several metabolic pathways. Vitamin C is considered an antioxidant. L-ascorbate : The L-enantiomer of ascorbate and conjugate base of L-ascorbic acid, arising from selective deprotonation of the 3-hydroxy group. Required for a range of essential metabolic reactions in all animals and plants. L-ascorbic acid : The L-enantiomer of ascorbic acid and conjugate acid of L-ascorbate. vitamin C : Any member of a group of vitamers that belong to the chemical structural class called butenolides that exhibit biological activity against vitamin C deficiency in animals. The vitamers include L-ascorbic acid and its salt, ionized and oxidized forms. | ascorbic acid; vitamin C | coenzyme; cofactor; flour treatment agent; food antioxidant; food colour retention agent; geroprotector; plant metabolite; skin lightening agent |