| nicotinic receptors | A class of cholinergic receptors on skeletal muscle cells that are linked to ion channels in the cell membrane. (05 Mar 2000) |
|---|---|
| opiate receptors | Regions of the brain which have the capacity to bind morphine; some, along the aqueduct of Sylvius and in the centre median, are in areas related to pain, but others, as in the striatum, are not related. (05 Mar 2000) |
| T-cell antigen receptors | Receptors present on T-cells that interact with both processed antigen and major histocompatibility antigens simultaneously. (05 Mar 2000) |
| Fc receptors | <immunology> Receptors for the Fc portion of immunoglobulins. Fc_R (30 kD) is the receptor for serum and secretory IgA1 or IgA2 and is expressed on most myeloid cells and subpopulations of T and B-cells. Fc_RI (CD64) High affinity receptor (72 kD on gels) for monomeric IgG1 found on monocytes, macrophages and some neutrophils. The extracellular portion has three immunoglobulin superfamily C2 domains, in contrast to Fc_RII, Fc_RIII that have only two. Involved in antibody dependent cell killing and in clearance of immune complexes. Fc_RII (CD32) Low affinity receptor 40 kD) for aggregated IgG that exists in several sub types coded by three closely related genes, A, B and C. All forms are found on monocytes, the B forms (that are alternatively spliced) are found on B-cells, the A and C forms are present on neutrophils. Binding of aggregated IgG will trigger phagocytosis and the oxidative burst in neutrophils. Fc_RIII (CD16) is the low affinity receptor (50-80 kD on gels) for aggregated IgG. It is found in transmembrane and GPI linked forms. The transmembrane form associates with the _ subunit of Fc_RI or the TCR_ chain and on B-cells with the _ chain of Fc_RI. Has structural similarity with Fc_RI, Fc_RII and Fc_RI_. Binding of aggregated IgG or IgG antigen complexes mediates phagocytosis or antibody dependent cellular cytotoxicity. Fc_RI is a heteromeric high affinity receptor for IgE found on mast cells and basophils. The _ chain (45-65 kD on gels, 25 kD of polypetide) is N glycosylated and has two immunoglobulin C2 loops in addition to the transmembrane domain, the _ chain (32 kD) has four transmembrane domains, the _ subunit is a homodimer (8 kD monomer) identical to the _ subunit of CD16 and has similarity with _ and _ chains associated with the T-cell receptor. Binding of antigen to the IgE Fc_R complex triggers the release of histamine and various inflammatory mediators. Fc_RIIa & b CD23) Low affinity receptor (45 kD) for IgE. Both a and b are present on mature B-cells, the b form on monocytes, IL-4 activated macrophages, eosinophils, platelets and dendritic cells. The protein has a C type lectin domain that mediates IgE binding and can be cleaved from the membrane to yield an active soluble form. (18 Nov 1997) |
| low-density lipoprotein receptors | Receptors on the surface of cells, especially liver cells, which bind to low density lipoprotein and promote clearance of LDL from the plasma. (05 Mar 2000) |
| acetate kinase | <enzyme> An enzyme that catalyses reversibly the phosphorylation of acetate in the presence of a divalent cation and ATP with the formation of acetylphosphate and ADP. It is important in the glycolysis process. Chemical name: ATP:acetate phosphotransferase Registry number: EC 2.7.2.1 (12 Dec 1998) |
| actin kinase | <enzyme> Phosphorylates actin at threonine-201 and probably at thr(202) and/or thr(203) Registry number: EC 2.7.1.- Synonym: actin-fragmin kinase (26 Jun 1999) |
| adenosine kinase | <enzyme> An enzyme that catalyses the formation of ADP plus AMP from adenosine plus ATP. It can serve as a salvage mechanism for returning adenosine to nucleic acids. Chemical name: ATP:adenosine 5'-phosphotransferase Registry number: EC 2.7.1.20 (12 Dec 1998) |
| adenylate kinase | <enzyme> An enzyme that catalyses the phosphorylation of AMP to ADP in the presence of ATP or inorganic triphosphate. Chemical name: ATP:AMP phosphotransferase Registry number: EC 2.7.4.3 (12 Dec 1998) |
| adenylic acid kinase | <enzyme> An enzyme that catalyses the phosphorylation of AMP to ADP in the presence of ATP or inorganic triphosphate. Chemical name: ATP:AMP phosphotransferase Registry number: EC 2.7.4.3 (12 Dec 1998) |
| adenylylsulfate kinase | adenosine 5'-phosphosulfate kinase |
| adhesion-related kinase | <chemical> New member of the immunoglobulin superfamily with 2 immunoglobulin-like domains Synonym: ark protein, ark receptor tyrosine kinase (26 Jun 1999) |
| adhesion structures linked tyrosine kinase | <enzyme> Isolated from mouse embryonic stem cells Registry number: EC 2.7.1.- Synonym: hyk protein (26 Jun 1999) |
| ADP - thymidine kinase | <enzyme> Induced by herpes simplex virus infection of mouse fibroblasts Registry number: EC 2.7.1.118 Synonym: ADP-thymidine 5'-phosphotransferase (26 Jun 1999) |
| AKT1 protein kinase | <enzyme> Human homolog of v-akt oncogene product Registry number: EC 2.7.10.- Synonym: akt1 protein, human (26 Jun 1999) |