| cobra venom cofactor | <enzyme> A glycine-rich, heat-labile beta-glycoprotein found in blood. It is a proactivator of complement 3 in the alternate pathway of complement activation. Factor b is converted by factor d to c3 convertase. Registry number: EC 3.4.21.47 (12 Dec 1998) |
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| molybdenum cofactor | A complex of molybdenum and molybdopterin required for a number of enzymes. A deficiency of this cofactor will result in lower activities of sulfite oxidase, xanthine dehydrogenase, and aldehyde oxidase causing elevated levels of sulfite, thiosulfite, xanthine, etc. (05 Mar 2000) |
| cofactor | <biochemistry> Inorganic complement of an enzyme reaction, usually a metal ions. See: coenzyme. (18 Nov 1997) |
| platelet cofactor I | A coagulation (clotting) factor. Classic haemophilia (haemophilia A) is due to a congenital deficiency in the amount (or activity) of factor VIII. Factor VIII is also known as antihemophiliac factor (AHF) or antihemophiliac globulin (AHG). The gene for factor VIII (that for classic haemophilia) is on the X chromosome so females can be silent carriers without symptoms and males can be haemophiliacs. (12 Dec 1998) |
| platelet cofactor II | <chemical> Storage-stable blood coagulation factor acting in the intrinsic pathway. Its activated form, ixa, forms a complex with factor viii and calcium on platelet factor 3 to activate factor x to xa. Deficiency of factor ix results in christmas disease (haemophilia b). Chemical name: Blood-coagulation factor IX (12 Dec 1998) |
| heparin cofactor II | <chemical> A sulfated plasma protein with the mw of approximately 66kda. The protein is an inhibitor of thrombin in plasma that is activated by dermatan sulfate or heparin. It is a member of the serpin superfamily. Pharmacological action: serine proteinase inhibitors. Chemical name: Heparin cofactor II (12 Dec 1998) |
| 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) |
| 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) |
| integral membrane protein | <protein> A protein that is firmly anchored in a membrane (unlike a peripheral membrane protein). most is known about the integral proteins of the plasma membrane, where important examples include hormone receptors, ion channels and transport proteins. An integral protein need not cross the entire membrane, those that do are referred to as transmembrane proteins. (18 Nov 1997) |
| erythrocyte membrane protein band 4.1 | See Elliptocytosis. (12 Dec 1998) |
| adamantine membrane | The primary enamel cuticle, consisting of two extremely thin layers (the inner one clear and structureless, the outer one cellular), covering the entire crown of newly erupted teeth and subsequently abraded by mastication; it is evident microscopically as an amorphous material between the attachment epithelium and the tooth. Synonym: cuticula dentis, adamantine membrane, dental cuticle, membrana adamantina, Nasmyth's cuticle, Nasmyth's membrane, skin of teeth. (05 Mar 2000) |
| allantoid membrane | An embryonic diverticulum of the hindgut of reptiles, birds, and mammals; in man its blood vessels give rise to those of the umbilical cord. (12 Dec 1998) |
| alveolocapillary membrane | The pulmonary diffusion barrier. (05 Mar 2000) |
| alveolodental membrane | <anatomy> Fibrous connective tissue surrounding the root of a tooth that separates it from and attaches it to the alveolar bone. (12 Dec 1998) |
| anal membrane | The dorsal portion of the embryonic cloacal membrane after its division by the urorectal septum. Anterior atlanto-occipital membrane, the fibrous layer that extends from the anterior arch of the atlas to the anterior margin of the foramen magnum. Synonym: membrana atlanto-occipitalis anterior. (05 Mar 2000) |