Purines
A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.
Purine Nucleotides
Purines attached to a RIBOSE and a phosphate that can polymerize to form DNA and RNA.
Purine Nucleosides
Purines with a RIBOSE attached that can be phosphorylated to PURINE NUCLEOTIDES.
Purine-Nucleoside Phosphorylase
Hypoxanthine
A purine and a reaction intermediate in the metabolism of adenosine and in the formation of nucleic acids by the salvage pathway.
Hypoxanthines
Purine bases related to hypoxanthine, an intermediate product of uric acid synthesis and a breakdown product of adenine catabolism.
Inosine
A purine nucleoside that has hypoxanthine linked by the N9 nitrogen to the C1 carbon of ribose. It is an intermediate in the degradation of purines and purine nucleosides to uric acid and in pathways of purine salvage. It also occurs in the anticodon of certain transfer RNA molecules. (Dorland, 28th ed)
Pentosyltransferases
Adenine
A purine base and a fundamental unit of ADENINE NUCLEOTIDES.
Phosphoribosyl Pyrophosphate
The key substance in the biosynthesis of histidine, tryptophan, and purine and pyrimidine nucleotides.
Pyrimidine Nucleotides
Pyrimidines with a RIBOSE and phosphate attached that can polymerize to form DNA and RNA.
Inosine Monophosphate
Inosine 5'-Monophosphate. A purine nucleotide which has hypoxanthine as the base and one phosphate group esterified to the sugar moiety.
Guanosine
A purine nucleoside that has guanine linked by its N9 nitrogen to the C1 carbon of ribose. It is a component of ribonucleic acid and its nucleotides play important roles in metabolism. (From Dorland, 28th ed)
Amidophosphoribosyltransferase
Purine-Pyrimidine Metabolism, Inborn Errors
Inborn errors of purine-pyrimidine metabolism refer to genetic disorders resulting from defects in the enzymes responsible for the metabolic breakdown and synthesis of purines and pyrimidines, leading to the accumulation of toxic metabolites or deficiency of necessary nucleotides, causing various clinical manifestations such as neurological impairment, kidney problems, and developmental delays.
Guanine
Hypoxanthine Phosphoribosyltransferase
An enzyme that catalyzes the conversion of 5-phosphoribosyl-1-pyrophosphate and hypoxanthine, guanine, or 6-mercaptopurine to the corresponding 5'-mononucleotides and pyrophosphate. The enzyme is important in purine biosynthesis as well as central nervous system functions. Complete lack of enzyme activity is associated with the LESCH-NYHAN SYNDROME, while partial deficiency results in overproduction of uric acid. EC 2.4.2.8.
Methylthioinosine
6-(Methylthio)-9-beta-D-ribofuranosylpurine. An analog of inosine with a methylthio group replacing the hydroxyl group in the 6-position.
Nucleosides
Phosphoribosylglycinamide Formyltransferase
Adenosine
Hydroxymethyl and Formyl Transferases
Xanthine
A purine base found in most body tissues and fluids, certain plants, and some urinary calculi. It is an intermediate in the degradation of adenosine monophosphate to uric acid, being formed by oxidation of hypoxanthine. The methylated xanthine compounds caffeine, theobromine, and theophylline and their derivatives are used in medicine for their bronchodilator effects. (Dorland, 28th ed)
Adenine Phosphoribosyltransferase
An enzyme catalyzing the formation of AMP from adenine and phosphoribosylpyrophosphate. It can act as a salvage enzyme for recycling of adenine into nucleic acids. EC 2.4.2.7.
Adenylosuccinate Lyase
Adenosine Deaminase
Pyrimidine Nucleosides
Pyrimidines with a RIBOSE attached that can be phosphorylated to PYRIMIDINE NUCLEOTIDES.
Phosphoribosylaminoimidazolecarboxamide Formyltransferase
Nucleobase Transport Proteins
Proteins involved in the transport of nucleobases such as PYRIMIDINES and PURINES across membranes.
Deoxyadenosines
Ribose-Phosphate Pyrophosphokinase
An enzyme that catalyzes the formation of phosphoribosyl pyrophosphate from ATP and ribose-5-phosphate. EC 2.7.6.1.
Lesch-Nyhan Syndrome
An inherited disorder transmitted as a sex-linked trait and caused by a deficiency of an enzyme of purine metabolism; HYPOXANTHINE PHOSPHORIBOSYLTRANSFERASE. Affected individuals are normal in the first year of life and then develop psychomotor retardation, extrapyramidal movement disorders, progressive spasticity, and seizures. Self-destructive behaviors such as biting of fingers and lips are seen frequently. Intellectual impairment may also occur but is typically not severe. Elevation of uric acid in the serum leads to the development of renal calculi and gouty arthritis. (Menkes, Textbook of Child Neurology, 5th ed, pp127)
Ribonucleosides
Inosine Nucleotides
Inosine nucleotides are purine nucleotides that contain inosine, a nucleoside with a hypoxanthine base, which can function as a weak agonist at adenosine receptors and play a role in the salvage pathways of nucleic acid metabolism.
Nucleotides
The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
Adenylosuccinate Synthase
Azaserine
Ribonucleotides
Allantoin
Guanosine Monophosphate
A guanine nucleotide containing one phosphate group esterified to the sugar moiety and found widely in nature.
Uric Acid
An oxidation product, via XANTHINE OXIDASE, of oxypurines such as XANTHINE and HYPOXANTHINE. It is the final oxidation product of purine catabolism in humans and primates, whereas in most other mammals URATE OXIDASE further oxidizes it to ALLANTOIN.
Pentosephosphates
Azaguanine
Formycins
Pyrazolopyrimidine ribonucleosides isolated from Nocardia interforma. They are antineoplastic antibiotics with cytostatic properties.
Adenine Nucleotides
Adenine nucleotides are molecules that consist of an adenine base attached to a ribose sugar and one, two, or three phosphate groups, including adenosine monophosphate (AMP), adenosine diphosphate (ADP), and adenosine triphosphate (ATP), which play crucial roles in energy transfer and signaling processes within cells.
Carbon-Nitrogen Ligases with Glutamine as Amide-N-Donor
Adenosine Monophosphate
Pyrimidines
Nucleoside Transport Proteins
Proteins involved in the transport of NUCLEOSIDES across cellular membranes.
Adenosine Triphosphate
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
Xanthine Dehydrogenase
Adenosine Kinase
An enzyme that catalyzes the formation of ADP plus AMP from adenosine plus ATP. It can serve as a salvage mechanism for returning adenosine to nucleic acids. EC 2.7.1.20.
Base Sequence
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Adenosine Deaminase Inhibitors
Drugs that inhibit ADENOSINE DEAMINASE activity.
Nucleotidases
Molecular Sequence Data
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
IMP Dehydrogenase
An enzyme that catalyzes the dehydrogenation of inosine 5'-phosphate to xanthosine 5'-phosphate in the presence of NAD. EC 1.1.1.205.
Cladribine
5'-Nucleotidase
Pentostatin
A potent inhibitor of ADENOSINE DEAMINASE. The drug induces APOPTOSIS of LYMPHOCYTES, and is used in the treatment of many lymphoproliferative malignancies, particularly HAIRY CELL LEUKEMIA. It is also synergistic with some other antineoplastic agents and has immunosuppressive activity.
Carbon-Nitrogen Ligases
Nucleic Acid Conformation
Formates
Receptors, Purinergic
Cell surface proteins that bind PURINES with high affinity and trigger intracellular changes which influence the behavior of cells. The best characterized classes of purinergic receptors in mammals are the P1 receptors, which prefer ADENOSINE, and the P2 receptors, which prefer ATP or ADP.
DNA
A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).
2-Aminopurine
A purine that is an isomer of ADENINE (6-aminopurine).
Substrate Specificity
Tubercidin
An antibiotic purine ribonucleoside that readily substitutes for adenosine in the biological system, but its incorporation into DNA and RNA has an inhibitory effect on the metabolism of these nucleic acids.
Nucleotide Deaminases
Catalyze the hydrolysis of nucleotides with the elimination of ammonia.
Aminohydrolases
Aminohydrolases are a class of enzymes that catalyze the hydrolysis of various nitrogenous compounds, including proteins, nucleotides, and amines, playing a crucial role in numerous biological processes such as metabolism and signaling.
Deoxyguanosine
A nucleoside consisting of the base guanine and the sugar deoxyribose.
Thioguanine
Guanine Nucleotides
Guanine nucleotides are cyclic or linear molecules that consist of a guanine base, a pentose sugar (ribose in the cyclic form, deoxyribose in the linear form), and one or more phosphate groups, playing crucial roles in signal transduction, protein synthesis, and regulation of enzymatic activities.
Deoxyguanine Nucleotides
Guanine nucleotides which contain deoxyribose as the sugar moiety.
Mutation
Escherichia coli
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
Thioinosine
Sulfhydryl analog of INOSINE that inhibits nucleoside transport across erythrocyte plasma membranes, and has immunosuppressive properties. It has been used similarly to MERCAPTOPURINE in the treatment of leukemia. (From Martindale, The Extra Pharmacopoeia, 30th ed, p503)
Nucleoside Deaminases
Catalyze the hydrolysis of nucleosides with the elimination of ammonia.
GMP Reductase
Uridine Triphosphate
Xanthine Oxidase
An iron-molybdenum flavoprotein containing FLAVIN-ADENINE DINUCLEOTIDE that oxidizes hypoxanthine, some other purines and pterins, and aldehydes. Deficiency of the enzyme, an autosomal recessive trait, causes xanthinuria.
Base Pairing
Pairing of purine and pyrimidine bases by HYDROGEN BONDING in double-stranded DNA or RNA.
Aminoimidazole Carboxamide
An imidazole derivative which is a metabolite of the antineoplastic agents BIC and DIC. By itself, or as the ribonucleotide, it is used as a condensation agent in the preparation of nucleosides and nucleotides. Compounded with orotic acid, it is used to treat liver diseases.
N-Glycosyl Hydrolases
Uridine
Gout
Hereditary metabolic disorder characterized by recurrent acute arthritis, hyperuricemia and deposition of sodium urate in and around the joints, sometimes with formation of uric acid calculi.
Coformycin
A ribonucleoside antibiotic synergist and adenosine deaminase inhibitor isolated from Nocardia interforma and Streptomyces kaniharaensis. It is proposed as an antineoplastic synergist and immunosuppressant.
Glycine
Vidarabine Phosphate
An adenosine monophosphate analog in which ribose is replaced by an arabinose moiety. It is the monophosphate ester of VIDARABINE with antiviral and possibly antineoplastic properties.
Structure-Activity Relationship
Models, Molecular
Binding Sites
Urate Oxidase
An enzyme that catalyzes the conversion of urate and unidentified products. It is a copper protein. The initial products decompose to form allantoin. EC 1.7.3.3.
6-Mercaptopurine
Phosphotransferases
Allopurinol
A XANTHINE OXIDASE inhibitor that decreases URIC ACID production. It also acts as an antimetabolite on some simpler organisms.
Molecular Structure
Pyrimidinones
Guanosine Triphosphate
Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.
Nucleic Acids
High molecular weight polymers containing a mixture of purine and pyrimidine nucleotides chained together by ribose or deoxyribose linkages.