Dictionary,Defintion,Meaning,What is G Protein, Galactosuria, G-Actin, G-Banding, G Protein Coupled Receptor, G-Quartet, GO Phase

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Dictionary of Bioinformatics, Biotechnology, Biochemistry Dictionary of Bioinformatics, Biotechnology, Biochemistry Part 1 Part 2 Part 3 Established Culture - Ex Vivo Gene Therapy Exergonic Reactions - EXPASY (Expert Protein Analysis System) Expressed Sequence Tags (ESTs) - Extremozymes F Plasmid - FAD Familial Adenomatous Polyposis Coli (FAP) - FASTA Format Fat Soluble Vitamins - Feulgens's Test Fibrinogen (Factor I) - Fine Structure Mapping Fingerprinting - Flow Cytometry Fluidised Bed - FMN (Flavin Mononucleotide) Focus Forming Assay - Forming Face Fos Related Antigens (FRA) - Freeze Fracture Electron Microscopy FRET-Fluorescence Resonant Energy Transfer - Fusion Biopharmaceuticals G Protein - Galactosuria Gamma Chain - Gas Solid Chromatography Gastrits - Gene Activator Protein Gene Chips (also gene arrays) - Gene Protection technology Gene Splicing - Genetic Algorithm Genetic Drift - Genome Survey sequences (GSS) Genomic Library - Gibbs Donnan Effect Gilberts Syndrome - Glucocorticoids Glucose Alanine Cycle - Gluten sensitive Enteropathy (coeliac disease) Glycaemic load (GL) - Glycolysis

Home >> Dictionary of Bioinformatics, Biochemistry, Biotechnology >> G Protein - Galactosuria

	G Guanine A purine base found in DNA or RNA. G-actin See globular actin. G cap The 5’-terminal methylated guanine nucleotide found in eukaryotic mRNAs. It is joined to the mRNA in a 5’ to 5’ linkage as a posttranscriptional modification.
G protein (GTP-binding protein) Guanine nucleotide-binding trimeric protein that plays an important role in signal transduction in mammalian cells. G-proteins are present on the inner surface of the plasma membrane. They transmit signals via transmembrane receptors to adenylate cyclase, which catalyses the formation of cyclic AMP. The trimer is inert when bound by GDP. When the α-subunit is bound by GTP, it is released from the βγ dimer. One of the released subunits (α or βγ dimer) activates or represses a target protein. The GTP-protein complex is able to activate adenylate cyclase, whereas the GDP-protein complex cannot cause activation. G-proteins are activated when the signaling molecule (a hormone) binds to the transmembrane receptor.
G protein-coupled receptor (GPCR) A member of a large class of cell-surface signaling receptors. These include receptors for epinephrine, glucagons and serotonin, among other. The GPCRs contain seven transmembrane α-helices. Binding of the ligand results in activation of a coupled trimeric G protein that initiates intracellular signaling pathways. G-quartet Short oligonucleotides containing runs of four Gs that form 4-stranded structures with the four chains oriented in the same direction. G0 phase The state of withdrawal from the cell cycle into a quiescent (resting) phase. This is common state for differentiated cells.
G-quartet
	G2 phase The period of the cell cycle between the end of DNA replication (S phase) and the beginning of mitosis. G12-banding G-banding carried out at high pH. This stains mouse and human chromosomes differently thereby permitting discrimination of the two chromosomes as in somatic cell hybrids. GABA (Gamma Amino Butyric Acid) An inhibitory neurotransmitter formed by decarboxylation of glutamate. GABA inhibits neurotransmission by opening the chloride ion channels. Antidepressants such as valium and other diazepams act on the GABA receptor and potentiate the action of GABA.

G1 phase
The period of the cell cycle between mitosis and the beginning of DNA replication (S phase). Preparations for chromosomal duplication are made in this phase.

G1-Cdk
A complex formed by G1-cyclin and the corresponding cyclin-dependent kinase (Cdk)

G1/S-Cdk A complex formed by G1/S-cyclin and the corresponding cyclin-dependent kinase (Cdk) in vertebrate cells.

G-banding
A technique that produces a striated pattern in metaphase chromosomes that differentiates the members of a haploid set.

Gag
A gene that encodes viral capsids protein(s).

GAG
See glycosaminoglycan.

Galactitol (dulcitol)
The product of the action of aldose reductase on galactose in the lens.

Galactokinase
An enzyme that plays a role in galactose metabolism. Deficiency of galactokinase, which occurs is galactosaemia, is associated primarily with cataract formation. Due to the enzyme defect, galactose accumulates in the blood and tissues.

Galactosaemia
A genetic disease due to the deficiency of UDP glucose 4-epimerase that converts galactose to glucose. The disease is characterised by organ enlargement, mental retardation and cataract as a result of accumulation of D-galactose and D-galactose 1-phosphate in the circulation.

Galactose
An optical isomer of glucose that differs from glucose at the fourth carbon. It is converted to glucose by the action of UDP glucose 4-epimerase.

Galactose

Galactose tolerance test
A test used to assess the metabolic functions of the liver based on the ability of the liver to metabolise galactose. Forty grams of galactose is given orally or 0.5 g galactose per kg body weight is injected intravenously and blood galactose estimated over the next two hours. In normal persons, blood galactose concentrations would fall progressively, approaching fasting levels at the end of 2h. The rate of utilisation of galactose is proportional to the functioning liver cell mass and is decreased in cirrhosis and hepatitis.

Galactose-1-phosphate uridyltransferase (GALT)
An enzyme involved in the metabolism of galactose. Deficiency of the enzyme causes classic galactosaemia. The enzyme block causes tissue accumulation of galactose and galactose-1-phosphate.

Galactosuria
Excretion of galactose in urine. Galactose is found in the urine of women during pregnancy, lactation and the weaning period. Galactosuria also occurs in galactosaemia, an inborn error of metabolism in which the conversion of galactose to glucose is impaired.

Gall
A tumorous growth in plants.

Gallstones
Crystalline structures formed by concretion or accretion of bile constituents. The stones may be made of cholesterol, pigments or may be of mixed type. Cholesterol stones, which account for 80 per cent of all stones are formed by supersaturation of bile with cholesterol. Gallstones can cause cholecystitis, bacterial infection and obstructive jaundice. Treatment involves surgery, oral administration of bile acids and shock-wave lithortripsy.

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Dictionary of Bioinformatics, Biotechnology, Biochemistry Part 4 Part 5 Part 6 Part 7 Glycosuria - Gonadotrophic Hormones (gonadotrophins) Gradient Gels - Green Fluorescent protein (GFP) Group II hormones - GTPase activating Protein (GAP) Guanosine - Haemagglutination Inhibition Assay Haemochromatosis - Hairy Rootculture Haploinsufficiency - Heavy Chain Disease Helical - Wheel Heparin Hepatitis D HDV Delta Agent - Heterohypekomers Heterologous Gene Expression - High Dose Dexamethasone Test Hippuric Acid Synthesis Test - Histones Hollow Fibre - Homologous Recombination Homology Modelling - Human Artificial Chromosome Human Genome Project - Hybridisation Stringency Hydatiform Mole - Hyperchromic Effect Hyperosmolal Non Ketotic Coma - Hyperviscosity Syndrome Hypoaldosteronism - Hypothroidism Idiotope-Immortalisation Immunoabsorbant - Immunological Memory

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