Purines with a RIBOSE attached that can be phosphorylated to PURINE NUCLEOTIDES.
An enzyme that catalyzes the reaction between a purine nucleoside and orthophosphate to form a free purine plus ribose-5-phosphate. EC 2.4.2.1.
Purine or pyrimidine bases attached to a ribose or deoxyribose. (From King & Stansfield, A Dictionary of Genetics, 4th ed)
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.
Enzymes of the transferase class that catalyze the transfer of a pentose group from one compound to another.
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)
Purines attached to a RIBOSE and a phosphate that can polymerize to form DNA and RNA.
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)
Pyrimidines with a RIBOSE attached that can be phosphorylated to PYRIMIDINE NUCLEOTIDES.
Proteins involved in the transport of NUCLEOSIDES across cellular membranes.
Pyrazolopyrimidine ribonucleosides isolated from Nocardia interforma. They are antineoplastic antibiotics with cytostatic properties.
Ribose substituted in the 1-, 3-, or 5-position by a phosphoric acid moiety.
A purine and a reaction intermediate in the metabolism of adenosine and in the formation of nucleic acids by the salvage pathway.
Guanine nucleotides which contain deoxyribose as the sugar moiety.
A nucleoside that is composed of ADENINE and D-RIBOSE. Adenosine or adenosine derivatives play many important biological roles in addition to being components of DNA and RNA. Adenosine itself is a neurotransmitter.
A subtype of equilibrative nucleoside transporter proteins that is sensitive to inhibition by 4-nitrobenzylthioinosine.
Adenosine molecules which can be substituted in any position, but are lacking one hydroxyl group in the ribose part of the molecule.
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.
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)
An enzyme that catalyzes the hydrolysis of ADENOSINE to INOSINE with the elimination of AMMONIA.
6-(Methylthio)-9-beta-D-ribofuranosylpurine. An analog of inosine with a methylthio group replacing the hydroxyl group in the 6-position.
Purine bases related to hypoxanthine, an intermediate product of uric acid synthesis and a breakdown product of adenine catabolism.
A purine base and a fundamental unit of ADENINE NUCLEOTIDES.
Nucleosides in which the purine or pyrimidine base is combined with ribose. (Dorland, 28th ed)
Uridine is a nucleoside, specifically a derivative of pyrimidine, that is composed of a uracil molecule joined to a ribose sugar molecule through a β-N1 glycosidic bond, and has significant roles in RNA synthesis, energy transfer, and cell signaling.
Catalyze the hydrolysis of nucleosides with the elimination of ammonia.
A nucleoside consisting of the base guanine and the sugar deoxyribose.
Pyrimidinones are heterocyclic organic compounds that consist of a pyrimidine ring fused with a ketone group, which have significant applications in medicinal chemistry due to their wide range of biological activities, including antibacterial, antiviral, and anticancer properties.
Nucleosides containing arabinose as their sugar moiety.
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.
A purine or pyrimidine base bonded to DEOXYRIBOSE.
Drugs that inhibit ADENOSINE DEAMINASE activity.
The rate dynamics in chemical or physical systems.
Inorganic or organic salts and esters of arsenic acid.
An enzyme that catalyzes the transfer of ribose from uridine to orthophosphate, forming uracil and ribose 1-phosphate.
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)
A pyrimidine nucleoside that is composed of the base CYTOSINE linked to the five-carbon sugar D-RIBOSE.
Guanine is a purine nucleobase, one of the four nucleobases in the nucleic acid of DNA and RNA, involved in forming hydrogen bonds between complementary base pairs in double-stranded DNA molecules.
A subtype of equilibrative nucleoside transporter proteins that is insensitive to inhibition by 4-nitrobenzylthioinosine.
Nucleosides in which the base moiety is substituted with one or more sulfur atoms.
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.
A compound that, on administration, must undergo chemical conversion by metabolic processes before becoming the pharmacologically active drug for which it is a prodrug.
An antineoplastic agent used in the treatment of lymphoproliferative diseases including hairy-cell leukemia.
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
Inosine 5'-Monophosphate. A purine nucleotide which has hypoxanthine as the base and one phosphate group esterified to the sugar moiety.
The key substance in the biosynthesis of histidine, tryptophan, and purine and pyrimidine nucleotides.
An enzyme that catalyzes reversibly the phosphorylation of deoxycytidine with the formation of a nucleoside diphosphate and deoxycytidine monophosphate. Cytosine arabinoside can also act as an acceptor. All natural nucleoside triphosphates, except deoxycytidine triphosphate, can act as donors. The enzyme is induced by some viruses, particularly the herpes simplex virus (HERPESVIRUS HOMINIS). EC 2.7.1.74.
An enzyme that is found in mitochondria and in the soluble cytoplasm of cells. It catalyzes reversible reactions of a nucleoside triphosphate, e.g., ATP, with a nucleoside diphosphate, e.g., UDP, to form ADP and UTP. Many nucleoside diphosphates can act as acceptor, while many ribo- and deoxyribonucleoside triphosphates can act as donor. EC 2.7.4.6.
Pentosephosphates are monosaccharides, specifically pentoses, that have a phosphate group attached, playing crucial roles in carbohydrate metabolism, such as being intermediates in the pentose phosphate pathway and serving as precursors for nucleotide synthesis.
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.
A class of enzymes that catalyze the conversion of a nucleotide and water to a nucleoside and orthophosphate. EC 3.1.3.-.
Coronary vasodilator with some antiarrhythmic activity.
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.
A pentose active in biological systems usually in its D-form.
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.
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.
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.
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.
Nucleotides in which the purine or pyrimidine base is combined with ribose. (Dorland, 28th ed)
A ribonucleoside antibiotic synergist and adenosine deaminase inhibitor isolated from Nocardia interforma and Streptomyces kaniharaensis. It is proposed as an antineoplastic synergist and immunosuppressant.
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.
A guanine nucleotide containing one phosphate group esterified to the sugar moiety and found widely in nature.
Syndromes in which there is a deficiency or defect in the mechanisms of immunity, either cellular or humoral.
Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.
A glycoprotein enzyme present in various organs and in many cells. The enzyme catalyzes the hydrolysis of a 5'-ribonucleotide to a ribonucleoside and orthophosphate in the presence of water. It is cation-dependent and exists in a membrane-bound and soluble form. EC 3.1.3.5.
A modified nucleoside which is present in the first position of the anticodon of tRNA-tyrosine, tRNA-histidine, tRNA-asparagine and tRNA-aspartic acid of many organisms. It is believed to play a role in the regulatory function of tRNA. Nucleoside Q can be further modified to nucleoside Q*, which has a mannose or galactose moiety linked to position 4 of its cyclopentenediol moiety.
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.
A rather large group of enzymes comprising not only those transferring phosphate but also diphosphate, nucleotidyl residues, and others. These have also been subdivided according to the acceptor group. (From Enzyme Nomenclature, 1992) EC 2.7.
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)
Efflux pumps that use the energy of ATP hydrolysis to pump arsenite across a membrane. They are primarily found in prokaryotic organisms, where they play a role in protection against excess intracellular levels of arsenite ions.
A general class of integral membrane proteins that transport ions across a membrane against an electrochemical gradient.
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.
Inorganic salts of phosphoric acid.
An enzyme which catalyzes the hydrolysis of nucleoside triphosphates to nucleoside diphosphates. It may also catalyze the hydrolysis of nucleotide triphosphates, diphosphates, thiamine diphosphates and FAD. The nucleoside triphosphate phosphohydrolases I and II are subtypes of the enzyme which are found mostly in viruses.
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
Agents used in the prophylaxis or therapy of VIRUS DISEASES. Some of the ways they may act include preventing viral replication by inhibiting viral DNA polymerase; binding to specific cell-surface receptors and inhibiting viral penetration or uncoating; inhibiting viral protein synthesis; or blocking late stages of virus assembly.
Adenine nucleotide containing one phosphate group esterified to the sugar moiety in the 2'-, 3'-, or 5'-position.
Thymidine is a pyrimidine nucleoside, consisting of a thymine base linked to a deoxyribose sugar by a β-N1-glycosidic bond, which plays a crucial role in DNA replication and repair processes as one of the four nucleosides in DNA.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
A class of enzymes involved in the hydrolysis of the N-glycosidic bond of nitrogen-linked sugars.
An enzyme that catalyzes the formation of phosphoribosyl pyrophosphate from ATP and ribose-5-phosphate. EC 2.7.6.1.
Carbon-containing phosphonic acid compounds. Included under this heading are compounds that have carbon bound to either OXYGEN atom or the PHOSPHOROUS atom of the (P=O)O2 structure.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
A class of sodium-independent nucleoside transporters that mediate the facilitative transport of NUCLEOSIDES.
A nucleoside antibiotic isolated from Streptomyces antibioticus. It has some antineoplastic properties and has broad spectrum activity against DNA viruses in cell cultures and significant antiviral activity against infections caused by a variety of viruses such as the herpes viruses, the VACCINIA VIRUS and varicella zoster virus.
A family of nucleotide diphosphate kinases that play a role in a variety of cellular signaling pathways that effect CELL DIFFERENTIATION; CELL PROLIFERATION; and APOPTOSIS. They are considered multifunctional proteins that interact with a variety of cellular proteins and have functions that are unrelated to their enzyme activity.
A dideoxynucleoside compound in which the 3'-hydroxy group on the sugar moiety has been replaced by a hydrogen. This modification prevents the formation of phosphodiester linkages which are needed for the completion of nucleic acid chains. Didanosine is a potent inhibitor of HIV replication, acting as a chain-terminator of viral DNA by binding to reverse transcriptase; ddI is then metabolized to dideoxyadenosine triphosphate, its putative active metabolite.
Pyrimidines with a RIBOSE and phosphate attached that can polymerize to form DNA and RNA.
Membrane proteins whose primary function is to facilitate the transport of molecules across a biological membrane. Included in this broad category are proteins involved in active transport (BIOLOGICAL TRANSPORT, ACTIVE), facilitated transport and ION CHANNELS.
Inhibitors of reverse transcriptase (RNA-DIRECTED DNA POLYMERASE), an enzyme that synthesizes DNA on an RNA template.
A GUANOSINE analog that acts as an antimetabolite. Viruses are especially susceptible. Used especially against herpes.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A group of enzymes within the class EC 3.6.1.- that catalyze the hydrolysis of diphosphate bonds, chiefly in nucleoside di- and triphosphates. They may liberate either a mono- or diphosphate. EC 3.6.1.-.
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The determination of the concentration of a given component in solution (the analyte) by addition of a liquid reagent of known strength (the titrant) until an equivalence point is reached (when the reactants are present in stoichiometric proportions). Often an indicator is added to make the equivalence point visible (e.g., a change in color).
Cytosine nucleotides are organic compounds that consist of a nitrogenous base (cytosine), a pentose sugar (ribose in RNA or deoxyribose in DNA), and at least one phosphate group, playing crucial roles in genetic information storage, transmission, and expression within nucleic acids.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A subclass of ADENOSINE RECEPTORS that are generally considered to be coupled to the GS, STIMULATORY G-PROTEIN which causes up regulation of CYCLIC AMP.
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
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).
A class of cell surface receptors that prefer ADENOSINE to other endogenous PURINES. Purinergic P1 receptors are widespread in the body including the cardiovascular, respiratory, immune, and nervous systems. There are at least two pharmacologically distinguishable types (A1 and A2, or Ri and Ra).
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).
Pyrrolidines are saturated, heterocyclic organic compounds containing a five-membered ring with four carbon atoms and one nitrogen atom (NRCH2CH2), commonly found as structural components in various alkaloids and used in the synthesis of pharmaceuticals and other organic materials.
A gram-positive organism found in dairy products, fresh and salt water, marine organisms, insects, and decaying organic matter.
The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.
A family of 6-membered heterocyclic compounds occurring in nature in a wide variety of forms. They include several nucleic acid constituents (CYTOSINE; THYMINE; and URACIL) and form the basic structure of the barbiturates.
A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
Organic compounds that contain phosphorus as an integral part of the molecule. Included under this heading is broad array of synthetic compounds that are used as PESTICIDES and DRUGS.
Leukemia associated with HYPERPLASIA of the lymphoid tissues and increased numbers of circulating malignant LYMPHOCYTES and lymphoblasts.
Nucleosides that have two hydroxy groups removed from the sugar moiety. The majority of these compounds have broad-spectrum antiretroviral activity due to their action as antimetabolites. The nucleosides are phosphorylated intracellularly to their 5'-triphosphates and act as chain-terminating inhibitors of viral reverse transcription.
A group of hydrolases which catalyze the hydrolysis of monophosphoric esters with the production of one mole of orthophosphate. EC 3.1.3.
Established cell cultures that have the potential to propagate indefinitely.
A dideoxynucleoside compound in which the 3'-hydroxy group on the sugar moiety has been replaced by an azido group. This modification prevents the formation of phosphodiester linkages which are needed for the completion of nucleic acid chains. The compound is a potent inhibitor of HIV replication, acting as a chain-terminator of viral DNA during reverse transcription. It improves immunologic function, partially reverses the HIV-induced neurological dysfunction, and improves certain other clinical abnormalities associated with AIDS. Its principal toxic effect is dose-dependent suppression of bone marrow, resulting in anemia and leukopenia.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
The sum of the weight of all the atoms in a molecule.
A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
The facilitation of biochemical reactions with the aid of naturally occurring catalysts such as ENZYMES.
A non-template-directed DNA polymerase normally found in vertebrate thymus and bone marrow. It catalyzes the elongation of oligo- or polydeoxynucleotide chains and is widely used as a tool in the differential diagnosis of acute leukemias in man. EC 2.7.7.31.
Pentosyltransferases that catalyze the reaction between a pyrimidine nucleoside and orthophosphate to form a free pyrimidine and ribose-5-phosphate.
Proteins prepared by recombinant DNA technology.
The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.
White blood cells formed in the body's lymphoid tissue. The nucleus is round or ovoid with coarse, irregularly clumped chromatin while the cytoplasm is typically pale blue with azurophilic (if any) granules. Most lymphocytes can be classified as either T or B (with subpopulations of each), or NATURAL KILLER CELLS.
The process of cleaving a chemical compound by the addition of a molecule of water.
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
Azoles of one NITROGEN and two double bonds that have aromatic chemical properties.
2'-Deoxyuridine. An antimetabolite that is converted to deoxyuridine triphosphate during DNA synthesis. Laboratory suppression of deoxyuridine is used to diagnose megaloblastic anemias due to vitamin B12 and folate deficiencies.
Proteins involved in the transport of nucleobases such as PYRIMIDINES and PURINES across membranes.
An ACYCLOVIR analog that is a potent inhibitor of the Herpesvirus family including cytomegalovirus. Ganciclovir is used to treat complications from AIDS-associated cytomegalovirus infections.
The characteristic three-dimensional shape of a molecule.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
A dideoxynucleoside compound in which the 3'-hydroxy group on the sugar moiety has been replaced by a hydrogen. This modification prevents the formation of phosphodiester linkages which are needed for the completion of nucleic acid chains. The compound is a potent inhibitor of HIV replication at low concentrations, acting as a chain-terminator of viral DNA by binding to reverse transcriptase. Its principal toxic side effect is axonal degeneration resulting in peripheral neuropathy.
A group of enzymes that transfers a phosphate group onto an alcohol group acceptor. EC 2.7.1.
Phosphate esters of THYMIDINE in N-glycosidic linkage with ribose or deoxyribose, as occurs in nucleic acids. (From Dorland, 28th ed, p1154)
Substances that inhibit or prevent the proliferation of NEOPLASMS.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
Transport proteins that carry specific substances in the blood or across cell membranes.
An enzyme, involved in the early steps of purine nucleotide biosynthesis, that catalyzes the formation of 5-phosphoribosylamine from glutamine and phosphoribosylpyrophosphate. EC 2.4.2.14.
Agents used to treat AIDS and/or stop the spread of the HIV infection. These do not include drugs used to treat symptoms or opportunistic infections associated with AIDS.
A purine or pyrimidine base bonded to a DEOXYRIBOSE containing a bond to a phosphate group.
An enzyme that catalyzes the transfer of a formyl group from N10-formyltetrahydrofolate to N1-(5-phospho-D-ribosyl)glycinamide to yield N2-formyl-N1-(5-phospho-D-ribosyl)glycinamide and tetrahydrofolate. It plays a role in the de novo purine biosynthetic pathway.
A reverse transcriptase encoded by the POL GENE of HIV. It is a heterodimer of 66 kDa and 51 kDa subunits that are derived from a common precursor protein. The heterodimer also includes an RNAse H activity (RIBONUCLEASE H, HUMAN IMMUNODEFICIENCY VIRUS) that plays an essential role the viral replication process.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
A group of enzymes that catalyze the hydrolysis of diphosphate bonds in compounds such as nucleoside di- and tri-phosphates, and sulfonyl-containing anhydrides such as adenylylsulfate. (Enzyme Nomenclature, 1992) EC 3.6.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
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)
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.
The relationship between the dose of an administered drug and the response of the organism to the drug.
The molecular designing of drugs for specific purposes (such as DNA-binding, enzyme inhibition, anti-cancer efficacy, etc.) based on knowledge of molecular properties such as activity of functional groups, molecular geometry, and electronic structure, and also on information cataloged on analogous molecules. Drug design is generally computer-assisted molecular modeling and does not include pharmacokinetics, dosage analysis, or drug administration analysis.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
A species of GRAM-POSITIVE ENDOSPORE-FORMING BACTERIA in the family BACILLACEAE, found in soil, hot springs, Arctic waters, ocean sediments, and spoiled food products.
A photoactivable URIDINE analog that is used as an affinity label.
The phosphate esters of DIDEOXYNUCLEOSIDES.
The spatial arrangement of the atoms of a nucleic acid or polynucleotide that results in its characteristic 3-dimensional shape.
Cytidine 5'-(tetrahydrogen triphosphate). A cytosine nucleotide containing three phosphate groups esterified to the sugar moiety.
Purine bases found in body tissues and fluids and in some plants.
A dideoxynucleoside analog that inhibits reverse transcriptase and has in vitro activity against HIV.
Proteins found in any species of bacterium.
A pyrimidine base that is a fundamental unit of nucleic acids.
Uracil nucleotides are chemical compounds that consist of a uracil base, a sugar molecule called ribose, and one or more phosphate groups, which play crucial roles in DNA replication, repair, and gene expression as well as in RNA synthesis.
Polymers made up of a few (2-20) nucleotides. In molecular genetics, they refer to a short sequence synthesized to match a region where a mutation is known to occur, and then used as a probe (OLIGONUCLEOTIDE PROBES). (Dorland, 28th ed)
Enzymes that catalyze the transfer of hydroxymethyl or formyl groups. EC 2.1.2.
An enzyme that catalyzes the conversion of aminoimidazole-4-carboxamide ribonucleotide to 5-formyl-aminoimidazole-4-carboxamide ribonucleotide in the purine de novo synthesis pathway. It requires the cofactor N(10)-FORMYLTETRAHYDROFOLATE as the formyl donor.