| carbon-carbon double bond isomerases | <enzyme> Enzymes that catalyze the shifting of a carbon-carbon double bond from one position to another within the same molecule. Registry number: EC 5.3.3 (12 Dec 1998) |
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| carbon-carbon ligases | <enzyme> Enzymes that catalyze the joining of two molecules by the formation of a carbon-carbon bond. These are the carboxylating enzymes and are mostly biotinyl-proteins. Registry number: EC 6.4 (12 Dec 1998) |
| carbon-carbon lyases | <enzyme> Enzymes that catalyze the cleavage of a carbon-carbon bond by means other than hydrolysis or oxidation. This subclass contains the decarboxylases, the aldehyde-lyases, and the oxo-acid-lyases. Registry number: EC 4.1 (12 Dec 1998) |
| activated acetaldehyde | The activated form of acetaldehyde that is formed during the decarboxylation of active pyruvate. Formed in alcohol fermentation and in carbohydrate metabolism. Synonym: a-hydroxyethylthiamin pyrophosphate. (05 Mar 2000) |
| activated amino acid | The product formed by the condensation of the acyl radical of an amino acid and adenosine 5'-monophosphate (originally in the form of adenosine 5'-triphosphate, with elimination of a pyrophosphoric group). Formed in the first step of protein biosynthesis. Synonym: activated amino acid. (05 Mar 2000) |
| activated atom | An atom possessing more than normal energy as a result of input of energy. See: excited state. Synonym: excited atom. (05 Mar 2000) |
| activated carboxylic acid | Derivative of a carboxyl group that is more susceptible to nucleophilic attack than a free carboxyl group; e.g., acid anhydrides, thioesters. (05 Mar 2000) |
| activated charcoal | <drug> A type of carbon produced through exposing a source material such as wood or bone to very high temperatures in the presence of steam, air or carbon monoxide. Activated carbon is very good at removing (adsorbing) contaminants and is used in water filters, to decolour solutions and is sometimes administered to poisoning victims. (15 Jan 1998) |
| activated choline | An intermediate in the formation of phosphatidylcholine (lecithin); formed by the action of cytidine 5'-triphosphate on phosphocholine, linking the choline phosphate group to the alpha-phosphate of the cytidine 5'-triphosphate to give a pyrophosphate. Synonym: activated choline, cytidine diphosphate choline. (05 Mar 2000) |
| activated clotting time | The most common test used for coagulation time in cardiovascular surgery. (05 Mar 2000) |
| activated complex | <chemistry> State of highest energy during a reaction. When reactants form the activated complex, bond breaking and bond formation is occurring. Synonym: transition state. (09 Jan 1998) |
| activated fatty acid | A fatty acyl-coenzyme A thiol ester. (05 Mar 2000) |
| activated glucose | A nucleoside diphosphoglucose such as UDP glucose. (05 Mar 2000) |
| activated macrophage | A mature macrophage, in an active metabolic state, that is cytotoxic to tumour/target cells, usually following exposure to certain cytokines. Synonym: armed macrophage. (05 Mar 2000) |
| activated partial thromboplastin time | The time needed for plasma to form a fibrin clot following the addition of calcium and a phospholipid reagent; used to evaluate the intrinsic clotting system. (05 Mar 2000) |