| OAS | old age security; oral allergy syndrome; osmotically active substance |
|---|---|
| OAW | oral airways |
| OC | obstetrical conjugate; occlusocervical; office call; on call; only child; optic chiasma; oral contra... |
| OCA | oculocutaneous albinism; olivopontocerebellar atrophy; oral contraceptive agent |
| OCC | object-centered coordinate [method]; oral cholecystography |
| G-protein | <cell biology, molecular biology> Intracellular membrane-associated proteins activated by several (e.g., beta adrenergic) receptors. They serve as second messengers or transducers of the receptor-initiated response to intracellular elements such as enzymes to initiate an effect. They are also mediators of activated cell-surface receptors and their enzymes or of ion channels. They are responsible for activating a chain of events that alters the concentration of intracellular signaling molecules such as cyclic AMP and calcium. In turn, these intracellular messengers alter the behaviour of other target proteins within the cell. These proteins have a high affinity for guanine nucleotides and hence are named "G" proteins. Synonym: G-protein, GTP-binding proteins. (12 Jul 2000) |
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| G-protein coupled receptor | <cell biology> Cell surface receptors that are coupled to G-proteins (GTP-binding protein). G-protein coupled receptors are thought to have seven membrane spanning domains and have been divided into 2 subclasses: those in which the binding site is in the extracellular domain for example receptors for glycoprotein hormones, such as thyroid stimulating hormone (TSH) and follicle-stimulating hormone (FSH) and those in which the ligand binding site is likely to be in the plane of the 7 transmembrane domains for example rhodopsin and receptors for small neurotransmitters and hormones for example muscarinic acetylcholine receptor. (18 Nov 1997) |
| G-protein, inhibitory GI | A g-protein that inhibits adenylyl cyclase and activates k+ channels. (12 Dec 1998) |
| G-protein, stimulatory gs | A G-protein that mediates the receptor activation of adenylyl cyclase. (12 Dec 1998) |
| chemotactic protein methylesterase | <enzyme> Demethylates methyl-accepting chemotaxis proteins Registry number: EC 3.1.1.- Synonym: chemotactic methylesterase, carboxymethylesterase of chemotaxis, cheb methylesterase (26 Jun 1999) |
| peripheral membrane protein | <protein> Membrane proteins that are bound to the surface of the membrane and not integrated into the hydrophobic region. Usually soluble and were originally thought to bind to integral proteins by ionic and other weak forces (and could therefore be removed by high ionic strength, for example). However, it is now clear that some peripheral membrane proteins are covalently linked to molecules that are part of the membrane bilayer (see acylated proteins and glypiation) and that there are others that fit the original definition but are perhps more appropriately considered proteins of the cytoskeleton (e.g. Band 4.1 and spectrin) or extracellular matrix (e.g. Fibronectin). (18 Nov 1997) |
| peripheral protein | <protein> A water-soluble protein that is loosely bound (by hydrogen bonds orelectrostatic forces) to a membrane. (09 Oct 1997) |
| periplasmic protein disulfide oxidoreductase | <enzyme> Isolated from haemophilus influenzae; may be required for assembly or folding of one or more disulfide-containing cell envelope proteins; ccmg isolated from paracoccus denitrificans Registry number: EC 1.8.4.- Synonym: por disulfide oxidoreductase, por gene product, periplasmic oxidoreductase, ccmg gene product (26 Jun 1999) |
| ribose binding protein | <protein> Periplasmic binding proteins of bacteria that interact either with the ribose transport system or with the methyl accepting chemotaxis protein MCP III (trg). (18 Nov 1997) |
| ribosomal protein | <protein> Proteins present within the ribosomal subunits. In prokaryotes there are 31 proteins in the large subunit and 21 in the small subunit. Eukaryotic subunits have 50 (large subunit) and 33 (small subunit) proteins. (18 Nov 1997) |
| ribosomal protein s6 kinase | <enzyme> A protein serine/threonine kinase which is involved in cell transformation by polyoma virus and is connected to the expression of igf2. The immunosuppressant rapamycin inhibits the activation of the kinase, leading to reduced translation of certain mRNAs and a decrease in protein synthesis. Registry number: EC 2.7.10.- (12 Dec 1998) |
| ribosomal protein S6 kinase kinase | <enzyme> Isolated from unfertilised xenopus eggs; a 41 kD enzyme that is associated, in vivo, with phosphorylation on threonine and tyrosine residues and, in vitro, with phosphorylation on serine as well Registry number: EC 2.7.1.- Synonym: rsk kinase (26 Jun 1999) |
| chk1 protein kinase | <enzyme> A yeast protein kinase homolog, involved in cell-cycle arrest when DNA damage has occurred or when unligated DNA is present; named chk1 for checkpoint kinase; genbank af016582 (human), af016583 (murine) Registry number: EC 2.7.1.- Synonym: chk1 kinase, chk1 gene product, rad27 protein, rad27 gene product, hchk1 (human), mchk1 (murine), mammalian chk1 (26 Jun 1999) |
| green fluorescent protein | <protein> A protein found in jellyfish which fluoresces, or glows green visible light when excited by UV light with a wavelength of 395 nanometres. It can function as a biological marker when attached to other proteins. The structure of the protein is cylindrical with the glowing component, an amino acid complex called a fluorophore, in the middle of it. (09 Oct 1997) |
| groel protein | A chaperonin 60 heat-shock protein isolated from escherichia coli. (12 Dec 1998) |