| nonreciprocal contact inhibition | <cell biology> Collision behaviour between different cell types in which one cell shows contact inhibition of locomotion and the other does not. An example is the interaction between sarcoma cells and fibroblasts (the former not being inhibited). (18 Nov 1997) |
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| density dependent inhibition of growth | <cell culture> The phenomenon exhibited by most normal (anchorage dependent) animal cells in culture that stop dividing once a critical cell density is reached. The critical density is considerably higher for most cells than the density at which a monolayer is formed, for this reason, most cell behaviourists prefer the term density dependent inhibition of growth as this avoids any confusion with contact inhibition of locomotion, a totally different phenomenon that is contact dependent. (12 Jan 1998) |
| inhibition | 1. Arrest or restraint of a process. 2. <psychology> The interference with or prevention of a behavioural or verbal response even though the stimulus for that response is present; in psychoanalysis the unconscious restraining of an instinctual process. Origin: L. Inhibere = to restrain, habere = to hold (04 Jul 1999) |
| inhibition factor | <growth factor> A soluble, nondialysable factor that is produced by sensitised lymphocytes following exposure to a specific antigen. It inhibits macrophage migration and causes adherence. It was originally defined on the basis of inhibition of emigration of mononuclear cells from capillary (haematocrit) tubes, more recently a 13 kD protein with migration inhibitory activity has been isolated. Acronym: MIF Synonym: inhibition factor. (22 Sep 2002) |
| tissue thromboplastin inhibition time | A test used to identify lupus anticoagulant; the thromboplastin source used in the prothrombin test is diluted to increase sensitivity to inhibitors. (05 Mar 2000) |
| end product inhibition | <biochemistry, physiology> The process of the end product of a particular metabolic reaction inhibiting an allosteric enzyme involved in that reaction as the reaction starts again, thus breaking the reaction cycle. (09 Oct 1997) |
| uncompetitive inhibition | An inhibitory effect on a metabolic function, such as an enzyme, not based on competition for the binding site of the naturally occurring substrate, but on a different effect on the molecule whose function is being inhibited. (05 Mar 2000) |
| feedback inhibition | <biochemistry, physiology> The process of the end product of a particular metabolic reaction inhibiting an allosteric enzyme involved in that reaction as the reaction starts again, thus breaking the reaction cycle. (09 Oct 1997) |
| zone of inhibition | <microbiology> The area of no bacterial browth around an antimicrobial agent in the disk-diffusion test. (09 Oct 1997) |
| lateral inhibition | A simple form of information processing. The classic example is found in the eye, whereby ganglion cells are stimulated if photoreceptors in a well defined field are illuminated, but their response is inhibited if neighbouring photoreceptors are excited (an on field/off surround cell) or vice versa an off field/on surround cell. The effect of lateral inhibition is to produce edge or boundary sensitive cells and to reduce the amount of information that is sent to higher centres, a form of peripheral processing. (18 Nov 1997) |
| leukocyte adherence inhibition test | Test for cell-mediated antitumour immunity and related serum blocking factors based on the finding that leukocytes from cancer patients, but not from controls, when mixed in vitro with antigenic extracts of tumours of the same histological type, undergo a diminution in their normal adherence to glass surfaces. Sera from tumour-bearing patients block the lai reaction of their own leukocytes or those of other patients with the same type of tumour. (12 Dec 1998) |
| acetyl-activating enzyme | A ligase that catalyses the reaction of acetate and CoA and ATP to form AMP, pyrophosphate, and acetyl-CoA. A key step in the activation of acetate. Synonym: acetate thiokinase, acetate-CoA ligase, acetyl-activating enzyme, acetyl-CoA synthetase. (05 Mar 2000) |
| acyl-activating enzyme | <enzyme> Fatty acid thiokinase (long-chain), a ligase forming acyl-CoA, AMP, and pyrophosphate from long-chain fatty acids, ATP, and coenzyme A. Activity is independent of phosphatidylcholine Registry number: EC 6.2.1.3 Synonym: acyl-activating enzyme, dodecanoyl-CoA synthetase, fatty acid thiokinase (long chain), acid-coenzyme a ligase, fatty acid-CoA ligase, acyl-CoA synthetase, acyl-CoA ligase, coash ligase, ciprofibroyl-CoA synthetase, pristanoyl-CoA synthetase, palmityl CoA synthetase, palmitoyl CoA synthetase, palmitoyl CoA ligase, fatty acyl-CoA synthetase, very long chain fatty acid acyl-CoA synthetase, vlcfa acyl-CoA synthetase, nafenopin-CoA ligase, palmitoyl-CoA synthase, faa2 gene product, faa2p protein, vlacs enzyme (26 Jun 1999) |
| adaptive enzyme | Inducible enzyme, an enzyme that can be detected in a growing culture of a microorganism, after the addition of a particular substance (inducer) to the culture medium, but was not detectable prior to the addition and can act on the inducer. A prototype is the beta-galactosidase of Escherichia coli, synthesised upon the addition of various galactosides, whether or not these are good substrates. Compare: constitutive enzyme. Synonym: adaptive enzyme. (05 Mar 2000) |
| allosteric enzyme | <biochemistry, chemistry> A regulatory enzyme whose activity is modified by the noncovalent binding of a particular metabolite at a site (the allosteric site) other than the active site. (09 Oct 1997) |