| catalytic centre | See: active centre. (05 Mar 2000) |
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| antibodies, catalytic | Antibodies that can catalyze a wide variety of chemical reactions. They are characterised by high substrate specificity and share many mechanistic features with enzymes. (12 Dec 1998) |
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| catalytic | Relating to or effecting catalysis. (05 Mar 2000) |
| catalytic antibody | <chemistry> Antibody raised against a transition state analogue (e.g. A phosphate analogue of a carboxylic acid ester transition state) that can then catalyse the analogous chemical reaction, though not as effectively as a true enzyme. (16 Mar 1998) |
| catalytic model | <epidemiology> A (rather misleading name for a) type of compartmental model in which the force of infection is treated as a parameter to be estimated. (05 Dec 1998) |
| catalytic site | <chemistry> The site on an enzyme where the substrate or substrates (the reactants of a chemical or biochemical reaction) attach in order to convert to the product or products of the reaction, at a much higher speed than the substrate would need to convert to the product alone. (16 Mar 1998) |
| RNA, catalytic | RNA which contains an intron sequence that has an enzyme-like catalytic activity. This intron sequence has been shown to fold up to form a complex surface that can function like an enzyme in reactions with other RNA molecules and thus synthesise new molecules even in the absence of protein. (12 Dec 1998) |
| active centre | The part of a macromolecule at which a substrate or ligand, upon binding, produces biological activity; for an enzyme, this is the catalytic centre, the site on an enzyme that catalyses the reaction. (05 Mar 2000) |
| anospinal centre | The centre in the spinal cord that controls the contraction of the anal sphincter. (05 Mar 2000) |
| asymmetric centre | <chemistry> Same as a chiral centre, a tetrahedral carbon atom that bears four different substituents. (09 Jan 1998) |
| Broca's centre | The posterior part of the inferior frontal gyrus of the left or dominant hemisphere, corresponding approximately to Brodmann's area 44; Broca identified this region as an essential component of the motor mechanisms governing articulated speech. Synonym: Broca's area, Broca's field, motor speech centre. (05 Mar 2000) |
| Budge's centre | The preganglionic motor neurons in the first thoracic segment of the spinal cord which give rise to the sympathetic innervation of the dilator muscle of the eye's pupil. Synonym: Budge's centre. (05 Mar 2000) |
| vasomotor centre | Diffuse area of the reticular formation in the lateral medulla containing neurons that control vascular tone; consists of separate vasodepressor and vasopressor areas. (05 Mar 2000) |
| reaction centre | <plant biology> The site in the chloroplast that receives the energy trapped by chlorophyll and accessory pigments and initiates the electron transfer process. A photosynthetic complex containing chlorophyll (or bacteriochlorophyll) and other components, within which occurs the initial electron transfer reactions of photophosphorylation. (09 Oct 1997) |
| germinal centre | Areas within lymph nodes where B lymphocytes rapidly divide. (09 Oct 1997) |
| germinal centre kinase | <enzyme> A human ste20 homolog; mw 97 kD; has been sequenced Registry number: EC 2.7.10.- Synonym: germinal centre kinase gck, gc kinase, bl44 gene product (26 Jun 1999) |