| 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) |
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| 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) |
| amino acid activating enzyme | <enzyme> Enzymes catalyzing the formation of a specific aminoacyl-tRNA from an amino acid and adenosine 5'-triphosphate with the concomitant formation of adenosine 5'-monophosphate and pyrophosphate. Synonym: amino acid activating enzyme, aminoacyl-tRNA ligases. (05 Mar 2000) |
| angiotensin-converting enzyme | <enzyme> This hydrolase enzyme cleaves the decapeptide angiotensin I (biologically inactive) to form active angiotensin II by angiotensin-converting enzyme which removes a dipeptide (histidylleucine) from angiotensin I. Angiotensin II causes contraction of vascular smooth muscle and thus raises blood pressure and stimulates aldosterone release from the adrenal glands. Angiotensin is finally broken down by angiotensinases. Elevations in angiotensin converting enzyme are seen sarcoidosis, histoplasmosis, alcoholic cirrhosis, asbestosis, berylliosis, diabetes, Hodgkin's disease, hyperthyroidism, amyloidosis, primary biliary cirrhosis, idiopathic pulmonary fibrosis, pulmonary embolism, scleroderma, silicosis, tuberculosis, Gaucher's disease and leprosy. The normal values are 18 to 67 U/ml over 20 years of age (people under 20 have higher levels). Drugs that inhibit ACE are used to treat hypertension and congestive heart failure. See: angiotensin-converting enzyme inhibitor Acronym: ACE (12 Aug 2000) |
| angiotensin-converting enzyme inhibitor | <pharmacology> A class of drugs used in the treatment of hypertension and heart failure. They exert their haemodynamic effect mainly by inhibiting the renin-angiotensin system and produce a reduction of peripheral arterial resistance. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility. (14 Aug 2000) |
| angiotensin-converting enzyme secretase | <enzyme> Converts ace from a membrane-bound to a soluble form; not inhibited by thiol, serine or acid enzyme inhibitor but is inhibited by edta and 1,10-phenanthroline Registry number: EC 3.4.99.- Synonym: ace secretase (26 Jun 1999) |
| Antibody Directed Enzyme Prodrug Therapy | <pharmacology> A method for targeting a drug to a specific tissue, in which the targeting agent and the drug are administered separately. The drug is designed to be inactive (a prodrug) until it is converted by an enzyme, which is the targeting agent. The enzyme is coupled to an antibody that directs it to the tissue of interest. When the enzyme arrives at the tissue, the prodrug is activated only at that site, sparing other tissues from potentially toxic side effects. Acronym: ADEPT (14 Nov 1997) |
| antitumour enzyme | <enzyme> An enzyme that stimulates the degradation of a particular metabolite that cannot be synthesised by tumour cells, inhibits the synthesis of a metabolite needed by tumour cells, or inhibits tumour-specific DNA utilization; e.g., asparaginase. (05 Mar 2000) |
| autolytic enzyme | <enzyme> An enzyme capable of causing lysis of the cell forming it. (05 Mar 2000) |
| beta-carotene cleavage enzyme | <enzyme> An enzyme catalyzing the reaction of beta-carotene plus O2 producing two retinals. Synonym: beta-carotene cleavage enzyme, carotenase, carotinase. (05 Mar 2000) |
| branching enzyme | 1,4-alpha-d-glucan branching enzyme |
| cardiac enzyme | <biochemistry> A group of enzymes found normally in heart tissue. Cardiac enzymes are released into the blood stream in increased concentration when the heart muscle becomes damaged. Examples include SGOT, CPK-MB and LDH. (27 Sep 1997) |
| pancreatic enzyme | <biochemistry> One of the proteins made by the pancreas that aid digestion of fats, carbohydrates and proteins. (09 Oct 1997) |
| malate-condensing enzyme | <enzyme> An important enzyme in the glyoxylic acid cycle which reversibly catalyses the synthesis of l-malate from acetyl-CoA and glyoxylate. Chemical name: L-Malate glyoxylate-lyase (CoA-acetylating) Registry number: EC 4.1.3.2 (12 Dec 1998) |
| malic enzyme | <enzyme> An enzyme that catalyses the conversion of (s)-malate and NAD+ to oxaloacetate and NADH. Chemical name: (S)-Malate:NAD+ oxidoreductase Registry number: EC 1.1.1.37 (12 Dec 1998) |