| HE | half-scan with extrapolation; hard exudate; hektoen enteric [agar]; hemagglutinating encephalomyelit... |
|---|---|
| HEI | Health Effects Institute; high-energy intermediate; homogenous enzyme immunoassay; human embryonic i... |
| HMRTE | human milk reverse transcriptase enzyme |
| HRE | hepatic reticuloendothelial [cell]; high-resolution electrocardiography; hormone receptor enzyme |
| HRTE | human reverse transcriptase enzyme |
| enzyme immunoassay | The general term for an expanding technical arsenal of testing which allows a full range of quantitative analyses for both antigen and antibodies. These tests use colour-changed products of enzyme-substrate interaction (or inhibition) to measure the antigen-antibody reaction. Examples of EIA procedures (EMIT, ELISA, MAC, MEIA) follow. Acronym: EIA (05 Mar 2000) |
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| 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) |
| enzyme induction | An increase in enzyme secretion in response to an environmental signal. The classic example is the induction of _ galactosidase in E. Coli. (18 Nov 1997) |
| enzyme inhibition theory of narcosis | That narcotics inhibit respiratory enzymes by suppression of the formation of high energy phosphate bonds within the cell. (05 Mar 2000) |
| enzyme-linked immunoabsorbent assay | <investigation> The enzyme-linked immunoabsorbent assay is serologic test used as a general screening tool for the detection of antibodies to the HIV virus. Reported as positive or negative. Since false positive tests due occur (for example recent flu shot), positives will require further evaluation using the western blot. ELISA technology links an a measurable enzyme to either an antigen or antibody. In this way, it can then measure the presence of an antibody or an antigen in the bloodstream. Acronym: ELISA (27 Sep 1997) |
| enzyme-linked immunosorbent assay | An immunoassay utilizing an antibody labelled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed. (12 Dec 1998) |
| enzyme-multiplied immunoassay technique | A type of immunoassay in which the ligand is labelled with an enzyme, and the enzyme-ligand-antibody complex is enzymatically inactive, allowing quantitation of unlabelled ligand. The test uses antibodies that react only with the particular drug for which the sample is being tested. The antibodies attach themselves to the drug if it is present in the sample. It is not designed to measure amounts of the drug present, only to detect its presence or absence. It is used predominantly, but not exclusively, for the detection of drugs of abuse in the urine. See: competitive binding assay, enzyme-linked immunosorbent assay. (05 Mar 2000) |
| enzyme precursor | <biochemistry> Inactive precursors that can be converted to active enzymes. Enzyme precursors containing extra-long polypeptide chains that block activity are activated by acid or enzymatic hydrolysis to remove the inhibiting portion. (12 Dec 1998) |
| enzyme reactivator | <biochemistry> Compounds which restore enzymatic activity by removing an inhibitory group bound to the reactive site of the enzyme. (12 Dec 1998) |
| enzyme regulation | <biochemistry> Control of the rate of a reaction catalyzed by an enzyme by some effector (e.g., inhibitors or activators) or by alteration of some condition (e.g., pH or ionic strength). (05 Mar 2000) |
| enzyme replacement therapy | A type of medical treatment for patients who lack an important enzyme, the missing enzyme is injected into the patient. (09 Oct 1997) |
| enzyme repression | The interference in synthesis of an enzyme due to the elevated level of an effector substance, usually a metabolite, whose presence would cause depression of the gene responsible for enzyme synthesis. (12 Dec 1998) |
| enzyme stabilisation | Reducing the chances that an enzyme will inactivate in vitro (see enzyme inactivation) by changing the environmental conditions (such as pH, temperature, concentration of salt, etc.) or by attaching organic groups to it or changing some of its amino acid subunits. (09 Oct 1997) |
| enzyme stability | The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat. (12 Dec 1998) |
| enzyme-substrate complex | A noncovalent complex of two molecules; often referring to the enzyme-substrate complex in an enzyme-catalyzed reaction. Compare: central complex, Michaelis complex. Synonym: enzyme-substrate complex. (05 Mar 2000) |