Classification Term: 2788
Pyrimidine nucleosides (ontology term: CHEMONTID:0000480)
Compounds comprising a pyrimidine base attached to a ribosyl or deoxyribosyl moiety." []
found 35 associated metabolites at class metabolite taxonomy ontology rank level.
Ancestor: Nucleosides, nucleotides, and analogues
Child Taxonomies: Pyrimidine 2'-deoxyribonucleosides, Pyrimidine 3'-deoxyribonucleosides, Pyrimidine 2',3'-dideoxyribonucleosides
Uridine
Uridine, also known as beta-uridine or 1-beta-D-ribofuranosylpyrimidine-2,4(1H,3H)-dione, is a member of the class of compounds known as pyrimidine nucleosides. Pyrimidine nucleosides are compounds comprising a pyrimidine base attached to a ribosyl or deoxyribosyl moiety. More specifically, uridine is a nucleoside consisting of uracil and D-ribose and a component of RNA. Uridine is soluble (in water) and a very weakly acidic compound (based on its pKa). Uridine can be synthesized from uracil. It is one of the five standard nucleosides which make up nucleic acids, the others being adenosine, thymidine, cytidine and guanosine. The five nucleosides are commonly abbreviated to their one-letter codes U, A, T, C and G respectively. Uridine is also a parent compound for other transformation products, including but not limited to, nikkomycin Z, 3-(enolpyruvyl)uridine 5-monophosphate, and 5-aminomethyl-2-thiouridine. Uridine can be found in most biofluids, including urine, breast milk, cerebrospinal fluid (CSF), and blood. Within the cell, uridine is primarily located in the mitochondria, in the nucleus and the lysosome. It can also be found in the extracellular space. As an essential nucleoside, uridine exists in all living species, ranging from bacteria to humans. In humans, uridine is involved in several metabolic disorders, some of which include dhydropyrimidinase deficiency, MNGIE (mitochondrial neurogastrointestinal encephalopathy), and beta-ureidopropionase deficiency. Moreover, uridine is found to be associated with Lesch-Nyhan syndrome, which is an inborn error of metabolism. Uridine is a nucleoside consisting of uracil and D-ribose and a component of RNA. Uridine plays a role in the glycolysis pathway of galactose. In humans there is no catabolic process to metabolize galactose. Therefore, galactose is converted to glucose and metabolized via the normal glucose metabolism pathways. More specifically, consumed galactose is converted into galactose 1-phosphate (Gal-1-P). This molecule is a substrate for the enzyme galactose-1-phosphate uridyl transferase which transfers a UDP molecule to the galactose molecule. The end result is UDP-galactose and glucose-1-phosphate. This process is continued to allow the proper glycolysis of galactose. Uridine is found in many foods (anything containing RNA) but is destroyed in the liver and gastrointestinal tract, and so no food, when consumed, has ever been reliably shown to elevate blood uridine levels. On the other hand, consumption of RNA-rich foods may lead to high levels of purines (adenine and guanosine) in blood. High levels of purines are known to increase uric acid production and may aggravate or lead to conditions such as gout. Uridine is a ribonucleoside composed of a molecule of uracil attached to a ribofuranose moiety via a beta-N(1)-glycosidic bond. It has a role as a human metabolite, a fundamental metabolite and a drug metabolite. It is functionally related to a uracil. Uridine is a metabolite found in or produced by Escherichia coli (strain K12, MG1655). Uridine is a Pyrimidine Analog. The chemical classification of uridine is Pyrimidines, and Analogs/Derivatives. Uridine is a natural product found in Ulva australis, Synechocystis, and other organisms with data available. Uridine is a nucleoside consisting of uracil and D-ribose and a component of RNA. Uridine has been studied as a rescue agent to reduce the toxicities associated with 5-fluorouracil (5-FU), thereby allowing the administration of higher doses of 5-FU in chemotherapy regimens. (NCI04) Uridine is a metabolite found in or produced by Saccharomyces cerevisiae. A ribonucleoside in which RIBOSE is linked to URACIL. Uridine is a molecule (known as a nucleoside) that is formed when uracil is attached to a ribose ring (also known as a ribofuranose) via a b-N1-glycosidic bond. ; Uridine is a molecule (known as a nucleoside) that is formed when uracil is attached to a ribose ring (also known as a ribofuranose) via a ?-N1-glycosidic bond. Uridine is found in many foods, some of which are celery leaves, canola, common hazelnut, and hickory nut. A ribonucleoside composed of a molecule of uracil attached to a ribofuranose moiety via a beta-N(1)-glycosidic bond. [Spectral] Uridine (exact mass = 244.06954) and Adenosine (exact mass = 267.09675) and Glutathione (exact mass = 307.08381) were not completely separated on HPLC under the present analytical conditions as described in AC$XXX. Additionally some of the peaks in this data contains dimers and other unidentified ions. [Spectral] Uridine (exact mass = 244.06954) and Glutathione (exact mass = 307.08381) were not completely separated on HPLC under the present analytical conditions as described in AC$XXX. Additionally some of the peaks in this data contains dimers and other unidentified ions. Uridine. CAS Common Chemistry. CAS, a division of the American Chemical Society, n.d. https://commonchemistry.cas.org/detail?cas_rn=58-96-8 (retrieved 2024-06-29) (CAS RN: 58-96-8). Licensed under the Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0). Uridine (β-Uridine) is a glycosylated pyrimidine-analog containing uracil attached to a ribose ring (or more specifically, aribofuranose) via a β-N1-glycosidic bond. Uridine (β-Uridine) is a glycosylated pyrimidine-analog containing uracil attached to a ribose ring (or more specifically, aribofuranose) via a β-N1-glycosidic bond. Uridine (β-Uridine) is a glycosylated pyrimidine-analog containing uracil attached to a ribose ring (or more specifically, aribofuranose) via a β-N1-glycosidic bond.
Cytidine
Cytidine is a nucleoside that is composed of the base cytosine linked to the five-carbon sugar D-ribose. Cytidine is a pyrimidine that besides being incorporated into nucleic acids, can serve as a substrate for the salvage pathway of pyrimidine nucleotide synthesis. It is a precursor of cytidine triphosphate (CTP) needed in the phosphatidylcholine (PC) and phosphatidylethanolamine (PE) biosynthetic pathways. These variations probably reflect the species differences in cytidine deaminase, the enzyme that converts cytidine to uridine in the body. The transport of cytidine into the brains extracellular fluid, and then into neurons and glia, are essential prerequisites for cytidine to be utilized in the brain. An efficient mechanism mediating the brain uptake of circulating cytidine has not yet been demonstrated. The biosynthesis of PC, the most abundant phosphatide in the brain, via the Kennedy pathway requires phosphocholine and cytidine triphosphate (CTP), a cytidine nucleotide involved in the rate-limiting step. The enzyme that converts CTP to endogenous CDP-choline (CTP:phosphocholine cytidylyltransferase) is unsaturated at physiological brain CTP levels. APOBEC is a family of enzymes that has been discovered with the ability to deaminate cytidines on RNA or DNA. The human apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G protein (APOBEC3G, or hA3G), provides cells with an intracellular antiretroviral activity that is associated with the hypermutation of viral DNA through cytidine deamination. Indeed, hA3G belongs to a family of vertebrate proteins that contains one or two copies of a signature sequence motif unique to cytidine deaminases (CTDAs) (PMID: 16769123, 15780864, 16720547). Cytidine is a nucleoside that is composed of the base cytosine linked to the five-carbon sugar D-ribose. Cytidine is a pyrimidine that besides being incorporated into nucleic acids, can serve as substrate for the salvage pathway of pyrimidine nucleotide synthesis; as precursor of the cytidine triphosphate (CTP) needed in the phosphatidylcholine (PC) and phosphatidylethanolamine (PE) biosynthetic pathway. These variations probably reflect the species differences in cytidine deaminase, the enzyme that converts cytidine to uridine in the body. The transports of cytidine into the brains extracellular fluid, and then into neurons and glia, are essential prerequisites for cytidine to be utilized in brain. An efficient mechanism mediating the brain uptake of circulating cytidine has not yet been demonstrated. The biosynthesis of PC, the most abundant phosphatide in the brain, via the Kennedy pathway requires phosphocholine and cytidine triphosphate (CTP), a cytidine nucleotide, which is involved in the rate-limiting step. The enzyme that converts CTP to endogenous CDP-choline (CTP: phosphocholine cytidylyltransferase) is unsaturated at physiological brain CTP levels. Cytidine is a white crystalline powder. (NTP, 1992) Cytidine is a pyrimidine nucleoside in which cytosine is attached to ribofuranose via a beta-N(1)-glycosidic bond. It has a role as a human metabolite, a Saccharomyces cerevisiae metabolite, an Escherichia coli metabolite and a mouse metabolite. It is functionally related to a cytosine. Cytidine is a metabolite found in or produced by Escherichia coli (strain K12, MG1655). Cytidine is a natural product found in Fritillaria thunbergii, Castanopsis fissa, and other organisms with data available. Cytidine is a pyrimidine nucleoside comprised of a cytosine bound to ribose via a beta-N1-glycosidic bond. Cytidine is a precursor for uridine. Both cytidine and uridine are utilized in RNA synthesis. Cytidine is a metabolite found in or produced by Saccharomyces cerevisiae. A pyrimidine nucleoside that is composed of the base CYTOSINE linked to the five-carbon sugar D-RIBOSE. A pyrimidine nucleoside in which cytosine is attached to ribofuranose via a beta-N(1)-glycosidic bond. [Spectral] Cytidine (exact mass = 243.08552) and 3,4-Dihydroxy-L-phenylalanine (exact mass = 197.06881) and NAD+ (exact mass = 663.10912) were not completely separated on HPLC under the present analytical conditions as described in AC$XXX. Additionally some of the peaks in this data contains dimers and other unidentified ions. [Spectral] Cytidine (exact mass = 243.08552) and 3,4-Dihydroxy-L-phenylalanine (exact mass = 197.06881) were not completely separated on HPLC under the present analytical conditions as described in AC$XXX. Additionally some of the peaks in this data contains dimers and other unidentified ions. [Spectral] Cytidine (exact mass = 243.08552) and S-Adenosyl-L-homocysteine (exact mass = 384.12159) were not completely separated on HPLC under the present analytical conditions as described in AC$XXX. Additionally some of the peaks in this data contains dimers and other unidentified ions. Cytidine is a pyrimidine nucleoside and acts as a component of RNA. Cytidine is a precursor of uridine. Cytidine controls neuronal-glial glutamate cycling, affecting cerebral phospholipid metabolism, catecholamine synthesis, and mitochondrial function[1][2][3]. Cytidine is a pyrimidine nucleoside and acts as a component of RNA. Cytidine is a precursor of uridine. Cytidine controls neuronal-glial glutamate cycling, affecting cerebral phospholipid metabolism, catecholamine synthesis, and mitochondrial function[1][2][3]. Cytidine is a pyrimidine nucleoside and acts as a component of RNA. Cytidine is a precursor of uridine. Cytidine controls neuronal-glial glutamate cycling, affecting cerebral phospholipid metabolism, catecholamine synthesis, and mitochondrial function[1][2][3].
5-Fluorouridine
5-Fluorouridine is a metabolite of fluorouracil. Fluorouracil (5-FU or f5U) (sold under the brand names Adrucil, Carac, Efudix, Efudex and Fluoroplex) is a drug that is a pyrimidine analog which is used in the treatment of cancer. It is a suicide inhibitor and works through irreversible inhibition of thymidylate synthase. It belongs to the family of drugs called antimetabolites. It is typically administered with leucovorin. (Wikipedia) 5-Fluorouridine, a metabolite of 5-fluorouracil (HY-90006), is a potent ribozyme self-cleavage inhibitor. 5-Fluorouridine incorporates into both total and poly A RNA and has antiproliferative activity. 5-Fluorouridine induces apoptosis[1][2][3].
Ribothymidine
Ribothymidine is an endogenous methylated nucleoside found in human fluids; methylated purine bases are present in higher amounts in tumor-bearing patients compared to healthy controls.DNA hypermethylation is a common finding in malignant cells and has been explored as a therapeutic target for hypomethylating agents. When chemical bonds to DNA, the DNA becomes damaged and proper and complete replication cannot occur to make the normal intended cell. A DNA adduct is an abnormal piece of DNA covalently-bonded to a cancer-causing chemical. This has shown to be the start of a cancerous cell, or carcinogenesis. DNA adducts in scientific experiments are used as bio-markers and as such are themselves measured to reflect quantitatively, for comparison, the amount of cancer in the subject. (PMID: 3506820, 17044778, 17264127, 16799933) [HMDB] Ribothymidine is an endogenous methylated nucleoside found in human fluids; methylated purine bases are present in higher amounts in tumor-bearing patients compared to healthy controls.DNA hypermethylation is a common finding in malignant cells and has been explored as a therapeutic target for hypomethylating agents. When chemical bonds to DNA, the DNA becomes damaged and proper and complete replication cannot occur to make the normal intended cell. A DNA adduct is an abnormal piece of DNA covalently-bonded to a cancer-causing chemical. This has shown to be the start of a cancerous cell, or carcinogenesis. DNA adducts in scientific experiments are used as bio-markers and as such are themselves measured to reflect quantitatively, for comparison, the amount of cancer in the subject. (PMID:3506820, 17044778, 17264127, 16799933). 5-Methyluridine is a is an endogenous methylated nucleoside found in human fluids. 5-Methyluridine is a is an endogenous methylated nucleoside found in human fluids.
5,10-Methylenetetrahydromethanopterin
This compound belongs to the family of Alkyl Glycosides. These are lipids containing a glycosyl moiety (one or several units) linked to the hydroxyl group of a fatty alcohol.
Cytarabine
Cytarabine, or cytosine arabinoside, a pyrimidine nucleoside analog, is found in mushrooms. Cytarabine is isolated from the mushroom Xerocomus nigromaculatus of unknown palatability. Cytarabine is an antineoplastic anti-metabolite used in the treatment of several forms of leukemia including acute myelogenous leukemia and meningeal leukemia. Cytarabine is an antimetabolite antineoplastic agent that inhibits the synthesis of DNA. Its actions are specific for the S phase of the cell cycle to stop normal cell development and division. Cytarabine is metabolized intracellularly into its active triphosphate form (cytosine arabinoside triphosphate). This metabolite then damages DNA by multiple mechanisms, including the inhibition of alpha-DNA polymerase, inhibition of DNA repair through an effect on beta-DNA polymerase, and incorporation into DNA. The latter mechanism is probably the most important. Cytotoxicity is highly specific for the S phase of the cell cycle. Cytarabine is a chemotherapy agent used mainly in the treatment of hematological malignancies such as acute myeloid leukemia (AML) and non-Hodgkin lymphoma. It is also known as ara C. Cytosine arabinoside is an antimetabolic agent with the chemical name of 1 -arabinofuranosylcytosine. Its mode of action is due to its rapid conversion into cytosine arabinoside triphosphate, which damages DNA when the cell cycle holds in the S phase (synthesis of DNA). Rapidly dividing cells, which require DNA replication for mitosis, are therefore most affected. Cytosine arabinoside also inhibits both DNA and RNA polymerases and nucleotide reductase enzymes needed for DNA synthesis L - Antineoplastic and immunomodulating agents > L01 - Antineoplastic agents > L01B - Antimetabolites > L01BC - Pyrimidine analogues C274 - Antineoplastic Agent > C186664 - Cytotoxic Chemotherapeutic Agent > C272 - Antimetabolite D007155 - Immunologic Factors > D007166 - Immunosuppressive Agents D000890 - Anti-Infective Agents > D000998 - Antiviral Agents D009676 - Noxae > D000963 - Antimetabolites COVID info from COVID-19 Disease Map D000970 - Antineoplastic Agents KEIO_ID C119; [MS2] KO008896 KEIO_ID C119 Corona-virus Coronavirus SARS-CoV-2 COVID-19 SARS-CoV COVID19 SARS2 SARS Cytarabine, a nucleoside analog, causes S phase cell cycle arrest and inhibits DNA polymerase. Cytarabine inhibits DNA synthesis with an IC50 of 16 nM. Cytarabine has antiviral effects against HSV. Cytarabine shows anti-orthopoxvirus activity. Cytarabine, a nucleoside analog, causes S phase cell cycle arrest and inhibits DNA polymerase. Cytarabine inhibits DNA synthesis with an IC50 of 16 nM. Cytarabine has antiviral effects against HSV. Cytarabine shows anti-orthopoxvirus activity.
N4-Acetylcytidine
N4-Acetylcytidine is a modified nucleoside. N4-acetylcytidine is an endogenous urinary nucleoside product of the degradation of transfer ribonucleic acid (tRNA); urinary nucleosides are biological markers for patients with colorectal cancer. tRNA has been shown to be excreted in abnormal amounts in the urine of cancer patients. tRNA from neoplastic tissue had a much more rapid turnover rate than the tRNA from the corresponding normal tissue. Evidence indicates that methylation of tRNA occurs only after synthesis of the intact macromolecule. Because there are no specific enzyme systems to incorporate the modified nucleosides into the macromolecular nucleic acid, these nucleosides once released in the process of tRNA turnover cannot be reutilized, nor are they further degraded, but are excreted in urine. (PMID: 15991285, 3506820) [HMDB] N4-Acetylcytidine is a modified nucleoside. N4-acetylcytidine is an endogenous urinary nucleoside product of the degradation of transfer ribonucleic acid (tRNA); urinary nucleosides are biological markers for patients with colorectal cancer. tRNA has been shown to be excreted in abnormal amounts in the urine of cancer patients. tRNA from neoplastic tissue had a much more rapid turnover rate than the tRNA from the corresponding normal tissue. Evidence indicates that methylation of tRNA occurs only after synthesis of the intact macromolecule. Because there are no specific enzyme systems to incorporate the modified nucleosides into the macromolecular nucleic acid, these nucleosides once released in the process of tRNA turnover cannot be reutilized, nor are they further degraded, but are excreted in urine. (PMID: 15991285, 3506820). N4-Acetylcytidine is an endogenous metabolite. N4-Acetylcytidine is an endogenous metabolite.
Orotidine
Orotidine is a nucleoside formed by attaching orotic acid to a ribose ring via a beta-N1-glycosidic bond. It is a water-soluble solid. Orotidine is found in bacteria, fungi, plants, and animals. In humans, orotidine occurs as its 5-phosphate (orotidylic acid), which is an intermediate in the biosynthesis of pyrimidine nucleosides (cytidine and uridine) that are found in nucleic acids (as the nucleotides containing the bases cytosine and uracil). Orotidine itself is not a component of nucleic acid. Orotidine monophosphate (OMP) is converted to uridine monophosphate by OMP decarboxylase, which is inhibited by mononucleotide precursors. Large amounts of orotidine are excreted in the urine of cancer patients treated with 6-azauridine, which is one such inhibitor, indicating that the subject has increased DNA synthesis due to cancer. Orotidine was first isolated from a mutant strain of the fungus Neurospora by A. Michael Michelson, William Drell, and Herschel K. Mitchell (PMID: 14853953). Isolated from Phaseolus vulgaris (kidney bean) Orotidine. CAS Common Chemistry. CAS, a division of the American Chemical Society, n.d. https://commonchemistry.cas.org/detail?cas_rn=314-50-1 (retrieved 2024-07-16) (CAS RN: 314-50-1). Licensed under the Attribution-Noncommercial 4.0 International License (CC BY-NC 4.0).
5-Methylcytidine
5-Methylcytidine belongs to the class of organic compounds known as pyrimidine nucleosides. Pyrimidine nucleosides are compounds comprising a pyrimidine base attached to a ribosyl or deoxyribosyl moiety. 5-Methylcytidine is a post-transcriptional modifications found in tRNA, snRNA, and rRNA. It is associated with the genetic change which is involved in the origin of cancer (PMID 6260434). [HMDB] 5-Methylcytidine is a pyrimidine nucleoside detected in multiple biofluids. 5-Methylcytidine is a pyrimidine nucleoside detected in multiple biofluids.
3-Methyluridine
3-Methyluridine is a modified nucleoside of cellular RNA. All modifications are formed post-transcriptionally in RNA from the normal nucleosides by modifying enzymes, especially specific RNA-methyltransferases and RNA-synthetases. Due to the lack of specific phosphorylases for modified nucleosides they cannot be recycled for synthesizing RNA, so they are excreted quantitatively in urine. (PMID 15906010) [HMDB] 3-Methyluridine is a modified nucleoside of cellular RNA. All modifications are formed post-transcriptionally in RNA from the normal nucleosides by modifying enzymes, especially specific RNA-methyltransferases and RNA-synthetases. Due to the lack of specific phosphorylases for modified nucleosides they cannot be recycled for synthesizing RNA, so they are excreted quantitatively in urine. (PMID 15906010). 3-Methyluridine (N3-Methyluridine) is a modified RNA nucleoside. 3-Methyluridine is often presents as?RNA modification which can be detected in 23S?rRNA?of?archaea, 16S and 23S rRNA of?eubacteria, and 18S, 25S, and 28S of eukaryotic ribosomal RNAs[1][2]. 3-Methyluridine (N3-Methyluridine) is a modified RNA nucleoside. 3-Methyluridine is often presents as?RNA modification which can be detected in 23S?rRNA?of?archaea, 16S and 23S rRNA of?eubacteria, and 18S, 25S, and 28S of eukaryotic ribosomal RNAs[1][2].
5-Taurinomethyl-2-thiouridine
5-taurinomethyl-2-thiouridine is a taurine-containing modified uridine which is present in human mitochondrial (mt) tRNA(Lys). (PMID: 15509579) [HMDB] 5-taurinomethyl-2-thiouridine is a taurine-containing modified uridine which is present in human mitochondrial (mt) tRNA(Lys). (PMID: 15509579).
2'-O-Methyluridine
2-O-Methyluridine belongs to the class of organic compounds known as pyrimidine nucleosides. Pyrimidine nucleosides are compounds comprising a pyrimidine base attached to a ribosyl or deoxyribosyl moiety. 2-O-Methyluridine was identified as one of forty plasma metabolites that could be used to predict gut microbiome Shannon diversity (PMID: 31477923). Shannon diversity is a metric that summarizes both species abundance and evenness, and it has been suggested as a marker for microbiome health.
3-(3-Amino-3-carboxypropyl)uridine
1-[(2S,3R,4S,5R)-3,4-Dihydroxy-5-(hydroxymethyl)oxolan-2-yl]-4-imino-3-methylpyrimidin-2-one
2'-O-Methylcytidine
2'-O-Methylcytidine is a 2'-substituted nucleoside as a inhibitor of HCV replication. 2'-O-Methylcytidine inhibits RNA-dependent RNA polymerase (NS5B)-catalyzed RNA synthesis in vitro, in a manner that is competitive with substrate nucleoside triphosphate[1].
1-beta-D-Arabinofuranosyl-5-fluoro-(1H,3H)-pyrimidine-2,4-dione
2'-C-Methylcytidine
[(2R,3R,4R,5S)-3,4-Diacetyloxy-5-(2,4-dioxopyrimidin-1-yl)oxolan-2-yl]methyl acetate
1-[(2R,3S,5R)-3,4-Dihydroxy-5-(hydroxymethyl)oxolan-2-yl]pyrimidine-2,4-dione
1-beta-D-Arabinofuranosyluracil (Uracil 1-β-D-arabinofuranoside) isolated from the Caribbean sponge Tectitethya crypta, is a methoxyadenosine derivative. 1-beta-D-Arabinofuranosyluracil has demonstrated a diverse bioactivity profile including anti-inflammatory activity, analgesic and vasodilation properties[1]. 1-beta-D-Arabinofuranosyluracil reduces a proliferation of mouse lymphoma cells[2]. 1-beta-D-Arabinofuranosyluracil (Uracil 1-β-D-arabinofuranoside) isolated from the Caribbean sponge Tectitethya crypta, is a methoxyadenosine derivative. 1-beta-D-Arabinofuranosyluracil has demonstrated a diverse bioactivity profile including anti-inflammatory activity, analgesic and vasodilation properties[1]. 1-beta-D-Arabinofuranosyluracil reduces a proliferation of mouse lymphoma cells[2]. 1-beta-D-Arabinofuranosyluracil (Uracil 1-β-D-arabinofuranoside) isolated from the Caribbean sponge Tectitethya crypta, is a methoxyadenosine derivative. 1-beta-D-Arabinofuranosyluracil has demonstrated a diverse bioactivity profile including anti-inflammatory activity, analgesic and vasodilation properties[1]. 1-beta-D-Arabinofuranosyluracil reduces a proliferation of mouse lymphoma cells[2].
1-[(2R,4R,5R)-3,4-Dihydroxy-5-(hydroxymethyl)-2-oxolanyl]-2-pyrimidinone
4-Thiouridine
1-beta-D-Arabinofuranosyl-5-fluorocytosine
N(4)-Octadecyl-1-arabinofuranosylcytosine
Arabinofuranosylcytosine
Isolated from the mushroom Xerocomus nigromaculatus of unknown palatability This compound has been identified in human blood as reported by (PMID: 31557052 ). Arabinofuranosylcytosine is not a naturally occurring metabolite and is only found in those individuals exposed to this compound or its derivatives. Technically Arabinofuranosylcytosine is part of the human exposome. The exposome can be defined as the collection of all the exposures of an individual in a lifetime and how those exposures relate to health. An individual's exposure begins before birth and includes insults from environmental and occupational sources. Arabinofuranosylcytosine (Ara-C), also known as cytarabine, is a chemotherapeutic agent that is widely used in the treatment of various types of cancer, particularly hematological malignancies such as acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). The biological functions of Ara-C are primarily related to its antineoplastic properties, which are derived from its mechanism of action within the cell. Here is a detailed description of its biological functions: 1. **Inhibition of DNA Synthesis**: Ara-C functions as a nucleoside analog, which means it resembles the natural building blocks of DNA. Once inside the cell, Ara-C is converted to its active metabolite, araCTP (arabinofuranosylcytosine triphosphate). AraCTP competes with the natural deoxycytidine triphosphate (dCTP) for incorporation into the growing DNA chain during the S phase of the cell cycle. Because Ara-C lacks a 3'-hydroxyl group, its incorporation into DNA leads to chain termination, effectively stopping DNA synthesis. 2. **Cell Cycle Specificity**: Ara-C is most effective against cells that are actively dividing. Since it targets cells in the S phase of the cell cycle, it is particularly harmful to rapidly dividing cancer cells, which often spend a significant portion of their cycle in this phase. 3. **Inhibition of DNA Repair**: Beyond its direct effect on DNA synthesis, Ara-C can also interfere with DNA repair mechanisms. This is because the incorporation of Ara-C into DNA can cause mispairing and induce DNA damage, which the cell may be unable to repair properly. 4. **Cell Death Induction**: The inhibition of DNA synthesis and the induction of DNA damage can lead to cell death through apoptosis or necrosis. Cells that cannot replicate their DNA or repair the damage caused by Ara-C activation are programmed to die, which is a desirable outcome in the context of cancer treatment. 5. **Immune System Modulation**: In some cases, Ara-C can also modulate the immune system, although this is not its primary function. It can affect the function and proliferation of immune cells, which can have implications for both its therapeutic effects and side effects. 6. **Enzymatic Conversion**: Ara-C must be activated within the cell by the enzyme deoxycytidine kinase (dCK), which phosphorylates it to Ara-CMP (monophosphate), then to Ara-CDP (diphosphate), and finally to Ara-CTP. The efficiency of this conversion can vary between different types of cancer cells and normal cells, contributing to the selectivity of Ara-C's action. 7. **Cross-Linking Potential**: Although less common, Ara-C can also form cross-links with DNA, further complicating DNA structure and function, which can contribute to its cytotoxic effects. The biological functions of Ara-C are complex and can vary depending on the dose, the specific cancer type, and the individual patient's metabolism. Its use is carefully monitored in clinical settings due to its potential for significant side effects, including myelosuppression (decreased production of blood cells), gastrointestinal toxicity, and central nervous system toxicity.
arabinofuranosylthymine
Behenoyl-arabinofuranosyl-cytosine
Epilincomycin
D000890 - Anti-Infective Agents > D000900 - Anti-Bacterial Agents > D055231 - Lincosamides D004791 - Enzyme Inhibitors > D011500 - Protein Synthesis Inhibitors
