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Nucleoside-Diphosphate Kinase: 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.NM23 Nucleoside Diphosphate Kinases: 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.Nucleoside Diphosphate Kinase D: A nucleoside diphosphate kinase subtype that is localized to the intermembrane space of MITOCHONDRIA. It is believed to play a role in the synthesis of triphosphonucleotides using ATP formed through OXIDATIVE PHOSPHORYLATION.Monomeric GTP-Binding Proteins: A class of monomeric, low molecular weight (20-25 kDa) GTP-binding proteins that regulate a variety of intracellular processes. The GTP bound form of the protein is active and limited by its inherent GTPase activity, which is controlled by an array of GTPase activators, GDP dissociation inhibitors, and guanine nucleotide exchange factors. This enzyme was formerly listed as EC 3.6.1.47Nucleosides: Purine or pyrimidine bases attached to a ribose or deoxyribose. (From King & Stansfield, A Dictionary of Genetics, 4th ed)Guanosine Diphosphate: A guanine nucleotide containing two phosphate groups esterified to the sugar moiety.Phosphotransferases: 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.Guanosine Triphosphate: Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.Halomonas: A genus of gram-negative, rod-shaped or pleomorphic bacteria which are halotolerant. Members of this genus are capable of growth in sodium chloride concentrations of up to 20% or more. (From Bergey's Manual of Determinative Bacteriology, 9th ed)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.Succinate-CoA Ligases: Enzymes that catalyze the first step leading to the oxidation of succinic acid by the reversible formation of succinyl-CoA from succinate and CoA with the concomitant cleavage of ATP to ADP (EC 6.2.1.5) or GTP to GDP (EC 6.2.1.4) and orthophosphate. Itaconate can act instead of succinate and ITP instead of GTP.EC 6.2.1.-.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.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)Amino Acid Sequence: 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.Dictyostelium: A genus of protozoa, formerly also considered a fungus. Its natural habitat is decaying forest leaves, where it feeds on bacteria. D. discoideum is the best-known species and is widely used in biomedical research.Kinetics: The rate dynamics in chemical or physical systems.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Guanosine Monophosphate: A guanine nucleotide containing one phosphate group esterified to the sugar moiety and found widely in nature.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.Adenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.Nucleoside Diphosphate SugarsPyruvate Kinase: ATP:pyruvate 2-O-phosphotransferase. A phosphotransferase that catalyzes reversibly the phosphorylation of pyruvate to phosphoenolpyruvate in the presence of ATP. It has four isozymes (L, R, M1, and M2). Deficiency of the enzyme results in hemolytic anemia. EC 2.7.1.40.Histidine: An essential amino acid that is required for the production of HISTAMINE.Adenylate Kinase: An enzyme that catalyzes the phosphorylation of AMP to ADP in the presence of ATP or inorganic triphosphate. EC 2.7.4.3.Enzyme Stability: The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.Peas: A variable annual leguminous vine (Pisum sativum) that is cultivated for its rounded smooth or wrinkled edible protein-rich seeds, the seed of the pea, and the immature pods with their included seeds. (From Webster's New Collegiate Dictionary, 1973)Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Purine Nucleosides: Purines with a RIBOSE attached that can be phosphorylated to PURINE NUCLEOTIDES.Cytidine Diphosphate: Cytidine 5'-(trihydrogen diphosphate). A cytosine nucleotide containing two phosphate groups esterified to the sugar moiety. Synonyms: CRPP; cytidine pyrophosphate.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.5'-Nucleotidase: 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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.Molecular Weight: The sum of the weight of all the atoms in a molecule.GTP-Binding Proteins: Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.Cloning, Molecular: 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.Pyrimidine Nucleosides: Pyrimidines with a RIBOSE attached that can be phosphorylated to PYRIMIDINE NUCLEOTIDES.Serine: A non-essential amino acid occurring in natural form as the L-isomer. It is synthesized from GLYCINE or THREONINE. It is involved in the biosynthesis of PURINES; PYRIMIDINES; and other amino acids.Nucleoside Transport Proteins: Proteins involved in the transport of NUCLEOSIDES across cellular membranes.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Chromatography, Gel: Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.Mutation: 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.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Crystallization: The formation of crystalline substances from solutions or melts. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)DNA Primers: Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.Protein Conformation: 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).Phosphates: Inorganic salts of phosphoric acid.Protein Binding: 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.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Phosphatidylinositol 3-Kinases: Phosphotransferases that catalyzes the conversion of 1-phosphatidylinositol to 1-phosphatidylinositol 3-phosphate. Many members of this enzyme class are involved in RECEPTOR MEDIATED SIGNAL TRANSDUCTION and regulation of vesicular transport with the cell. Phosphatidylinositol 3-Kinases have been classified both according to their substrate specificity and their mode of action within the cell.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Electrophoresis, Gel, Two-Dimensional: Electrophoresis in which a second perpendicular electrophoretic transport is performed on the separate components resulting from the first electrophoresis. This technique is usually performed on polyacrylamide gels.MAP Kinase Signaling System: An intracellular signaling system involving the MAP kinase cascades (three-membered protein kinase cascades). Various upstream activators, which act in response to extracellular stimuli, trigger the cascades by activating the first member of a cascade, MAP KINASE KINASE KINASES; (MAPKKKs). Activated MAPKKKs phosphorylate MITOGEN-ACTIVATED PROTEIN KINASE KINASES which in turn phosphorylate the MITOGEN-ACTIVATED PROTEIN KINASES; (MAPKs). The MAPKs then act on various downstream targets to affect gene expression. In mammals, there are several distinct MAP kinase pathways including the ERK (extracellular signal-regulated kinase) pathway, the SAPK/JNK (stress-activated protein kinase/c-jun kinase) pathway, and the p38 kinase pathway. There is some sharing of components among the pathways depending on which stimulus originates activation of the cascade.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Protein Kinases: A family of enzymes that catalyze the conversion of ATP and a protein to ADP and a phosphoprotein.Protein-Serine-Threonine Kinases: A group of enzymes that catalyzes the phosphorylation of serine or threonine residues in proteins, with ATP or other nucleotides as phosphate donors.Pseudomonas aeruginosa: A species of gram-negative, aerobic, rod-shaped bacteria commonly isolated from clinical specimens (wound, burn, and urinary tract infections). It is also found widely distributed in soil and water. P. aeruginosa is a major agent of nosocomial infection.Equilibrative Nucleoside Transporter 1: A subtype of equilibrative nucleoside transporter proteins that is sensitive to inhibition by 4-nitrobenzylthioinosine.Uridine Diphosphate: A uracil nucleotide containing a pyrophosphate group esterified to C5 of the sugar moiety.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Structure-Activity Relationship: 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.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Cattle: 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.Alkyl and Aryl Transferases: A somewhat heterogeneous class of enzymes that catalyze the transfer of alkyl or related groups (excluding methyl groups). EC 2.5.Polyisoprenyl Phosphates: Phosphoric or pyrophosphoric acid esters of polyisoprenoids.Cyclic AMP: An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.Mitochondria: Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)Pyrophosphatases: 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.-.UDPglucose 4-Epimerase: A necessary enzyme in the metabolism of galactose. It reversibly catalyzes the conversion of UDPglucose to UDPgalactose. NAD+ is an essential component for enzymatic activity. EC 5.1.3.2.Protein Kinase Inhibitors: Agents that inhibit PROTEIN KINASES.