| radiation inactivation | The technique of inactivating proteins in freeze dried (lyophilised) preparations using high energy particles (e.g. Electrons). One high energy particle can apparently inactivate all of the components of a multisubunit polypeptide, the method is therefore used to determine the molecular weight of functional oligomers. (18 Nov 1997) |
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| X inactivation | <cell biology> The inactivation of one or other of each pair of X chromosomes to form the Barr body in female mammalian somatic cells. Thus tissues whose original zygote carried heterozygous X borne genes should have individual cells expressing one or other but not both of the X borne gene products. The inactivation is thought to occur early in development and leads to mosaicism of expression of such genes in the body. See: Lyon hypothesis. (18 Nov 1997) |
| inactivation | <neurology, physiology> For example of voltage gated sodium channels: process by which sodium channels that have been activated or opened by depolarisation subsequently close during the depolarisation. Distinguished from activation by its slower kinetics. (18 Nov 1997) |
| insertional inactivation | The inactivation of a gene due to the insertion of exogenous genetic material into that gene. (14 Nov 1997) |
| enzyme inactivation | The disappearance of an enzyme's activity during in vitro conditions, such as during a lab preparation of the enzyme, where the enzyme is exposed to conditions not normally found within its environment inside a living cell (like different pH, excess or too little salt, temperature changes, etc.) (09 Oct 1997) |
| male chromosome complement | The large majority of males have a 46, xy chromosome complement (46 chromosomes including an x and a y chromosome). A minority of males have other chromosome constitutions such as 47,xxy (47 chromosomes including two x chromosomes and a y chromosome) and 47,xyy (47 chromosomes including an x and two y chromosomes). (12 Dec 1998) |
| genetic complement | <biology, genetics> The set of chromosomes contained within any one particular cell. (07 May 1998) |
| receptors, complement | Molecules on the surface of some B-lymphocytes and macrophages, that recognise and combine with the c3b, c3d, c1q, and c4b components of complement. (12 Dec 1998) |
| receptors, complement 3b | Molecular sites on or in some B-lymphocytes and macrophages that recognise and combine with complement 3b. The primary structure of these receptors reveal that they contain transmembrane and cytoplasmic domains, with their extracellular portion composed entirely of thirty short consensus repeats each having 60 to 70 amino acids. (12 Dec 1998) |
| receptors, complement 3d | Molecular sites on or in B-lymphocytes, follicular dendritic cells, lymphoid cells, and epithelial cells that recognise and combine with complement 3d. Human cr2 serves as a receptor for both c3dg and the gp350/220 glycoprotein of herpes virus 4, human, and binds the monoclonal antibody okb7, which blocks binding of both ligands to the receptor. (12 Dec 1998) |
| chromosome complement | The whole set of chromosomes for the species. In humans, the chromosome complement (which is also called the karyotype) consists of 46 chromosomes. (12 Dec 1998) |
| complement | <immunology> A term originally used to refer to the heat labile factor in serum that causes immune cytolysis, the lysis of antibody coated cells and now referring to the entire functionally related system comprising at least 20 distinct serum proteins that is the effector not only of immune cytolysis but also of other biologic functions. Complement activation occurs by two different sequences, the classic and alternative pathways. The proteins of the classic pathway are termed components of complement and are designated by the symbols C1 through C9. C1 is a calcium dependent complex of three distinct proteins C1q, C1r and C1s. The proteins of the alternative pathway (collectively referred to as the properdin system) and complement regulatory proteins are known by semisystematic or trivial names. Fragments resulting from proteolytic cleavage of complement proteins are designated with lower case letter suffixes, for example, C3a. Inactivated fragments may be designated with the suffix i, for example C3bi. Activated components or complexes with biological activity are designated by a bar over the symbol for example C1 or C4b, 2a. The classic pathway is activated by the binding of C1 to classic pathway activators, primarily antigen-antibody complexes containing IgM, IgG1, IgG3, C1q binds to a single IgM molecule or two adjacent IgG molecules. The alternative pathway can be activated by IgA immune complexes and also by nonimmunologic materials including bacterial endotoxins, microbial polysaccharides and cell walls. Activation of the classic pathway triggers an enzymatic cascade involving C1, C4, C2 and C3, activation of the alternative pathway triggers a cascade involving C3 and factors B, D and P. Both result in the cleavage of C5 and the formation of the membrane attack complex. Complement activation also results in the formation of many biologically active complement fragments that act as anaphylatoxins, opsonins or chemotactic factors. (05 Jan 1998) |
| complement 1 | The first complement component to act in the cytolysis reaction. It is a trimolecular complex held together with ca ions and when activated, has esterase activity which initiates the next step in the sequence. (12 Dec 1998) |
| complement 1 inactivators | Compounds which inhibit, antagonise, or inactivate complement 1. A well-known inhibitor is a serum glycoprotein believed to be alpha-2-neuroaminoglycoprotein. It inhibits the activated (esterase) form of complement 1 as well as kinin-forming, coagulation, and fibrinolytic systems. Deficiency of this inactivator has been found in patients with hereditary angioneurotic oedema. These compounds are members of the serpin superfamily. (12 Dec 1998) |
| complement 1q | <chemical> Subcomponent of complement 1 (c1) which recognises and binds to the heavy chain of IgG or IgM initiating the classical complement pathway. The interaction of c1q and immunoglobulin activates c1r and c1s. The activated c1r and c1s molecules are cleaved off the complex by c1-inhibitor, allowing the collagen-like region of c1q to become accessible for interaction with cell membrane c1q receptors. Chemical name: Complement C1q (12 Dec 1998) |