| PD | Doctor of Pharmacy; Dublin Pharmacopoeia; interpupillary distance; Paget disease; pancreatic duct; p... |
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| PEP | peptidase; phospho(enol)pyruvate; peer evaluation program; phosphoenolpyruvate; pigmentation, edema,... |
| PMP | pain management program; patient management program; patient medication profile; peripheral myelin p... |
| PP | diphosphate group; emphysema [pink puffers]; near point of accommodation [Lat. punctum proximum]; pa... |
| PPD | packs per day; paraphenylenediamine; percussion and postural drainage; permanent partial disability;... |
| repressor protein | <molecular biology> A protein that binds to an operator of a gene preventing the transcription of the gene. The binding affinity of repressors for the operator may be affected by other molecules. Inducers bind to repressors and decrease their binding to the operator, while co repressors increase the binding. The paradigm of repressor proteins is the lactose repressor protein that acts on the lac operon and for which the inducers are _ galactosides such as lactose, it is a polypeptide of 360 amino acids that is active as a tetramer. Other examples are the lambda repressor protein of lambda bacteriophage that prevents the transcription of the genes required for the lytic cycle leading to lysogeny and the cro protein, also of lambda, which represses the transcription of the lambda repressor protein establishing the lytic cycle. Both of these are active as dimers and have a common structural feature the helix turn helix motif that is thought to bind to DNA with the helices fitting into adjacent major grooves. (18 Nov 1997) |
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| VLA protein | <protein> VLA 1 and VLA 2 were originally defined as antigens appearing on the surfaces of T lymphocytes 2-4 weeks after in vitro activation, they are now know to be part of the _ integrin family. Additional members of the subset are now known (VLA 3, VLA 4, VLA 5 and VLA 6), the _ subunits all being identical. Some of the VLA proteins are receptors for collagen, laminin or fibronectin and many are now known to be expressed on cells other than leucocytes. (18 Nov 1997) |
| pelle-like protein kinase | <enzyme> Mplk - mouse pelle-like kinase; mammalian homolog of drosophila pelle protein; expression is developmentally regulated and is greatest in liver; genbank l08476 Registry number: EC 2.7.10.- Synonym: mplk (protein) (26 Jun 1999) |
| ceramide-activated protein kinase | <enzyme> Mw 97 kD; stimulation of kinase takes place during sphingomyelin pathway; has membrane-bound activity capable of phosphorylating a peptide derived from the sequence surrounding thr(699) of the epidermal growth factor receptor; has role in signal transduction for tumour necrosis factor Registry number: EC 2.7.10.- Synonym: cap kinase (26 Jun 1999) |
| ceramide-activated protein phosphatase | <enzyme> Belongs to the heterotrimeric subfamily of the pp2a group of serine-threonine protein phosphatases; involved in ceramide-mediated signal transduction; inhibited by okadaic acid Registry number: EC 3.1.3.- Synonym: ceramide-stimulated phosphatase, capp (enzyme) (26 Jun 1999) |
| Vps15 protein kinase | <enzyme> Functions with vps34p as a membrane-associated complex which facilitates the delivery of proteins into the vacuole in yeast; amino acid sequence has been determined Registry number: EC 2.7.10.- Synonym: vps15 gene product, vps15p (26 Jun 1999) |
| retinoblastoma protein | <molecular biology, protein> Product of the retinoblastoma tumour suppressor gene. It is a nuclear phosphoprotein hypothesised to normally act as an inhibitor of cell proliferation. Rb protein is absent in retinoblastoma cell lines. It also has been shown to form complexes with the adenovirus e1a protein, the sv40 t antigen, and the human papilloma virus e7 protein. (03 Jul 1999) |
| retinol-binding protein | <molecular biology> Proteins which bind with retinol. The retinol-binding protein found in plasma has an alpha-1 mobility on electrophoresis and a molecular weight of 21,000-22,000. The protein has one binding site for retinol and is responsible for the transport of vitamin A. The retinol- protein complex (molecular weight 80,000 to 90,000) circulates in plasma in the form of a protein-protein complex with prealbumin. The retinol-binding protein found in tissue has a molecular weight of 14,000 and carries retinol as a non-covalently-bound ligand. (03 Jul 1999) |
| PEP protein tyrosine phosphatase | <enzyme> Pest - pro, glu, ser and thr; an intracellular ptpase expressed primarily by cells of haematopoietic origin; involved in regulating nuclear tyrosine phosphorylation; amino acid sequence has been determined Registry number: EC 3.1.3.- Synonym: pep ptpase, pest-enriched phosphatase, ptp-pest (26 Jun 1999) |
| membrane protein | <protein> A protein with regions permanently attached to a membrane (peripheral membrane protein) or inserted into a membrane integral membrane protein). Insertion into a membrane implies hydrophobic domains in the protein. All transport proteins are integral membrane proteins. (18 Nov 1997) |
| channel protein | <chemistry, physiology> A protein that facilitates the diffusion of molecules/ions across lipid membranes by forming a hydrophilic pore. most frequently multimeric with the pore formed by subunit interactions. (18 Nov 1997) |
| 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) |
| 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) |