| RPS | renal pressor substance; revolutions per second |
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| RQ | recovery quotient; [Hazardous Substance] Reportable Quantities [List]; reportable quantity; respirat... |
| RS | radioscaphoid; random sample; rating schedule; Raynaud syndrome; recipient's serum; rectal sinus; re... |
| Rst | in paper or thin layer chromatography, the distance that a spot of a substance has moved, relative t... |
| SAAS | Substance Abuse Attitude Survey |
| enzyme-catalyzed ligation | <enzyme> An enzyme-mediated joining of phosphodiester linkage of two stretches of DNA or RNA, or of peptide linkage of two polypeptides. (05 Mar 2000) |
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| enzyme defect | A disorder resulting from a deficiency (or functional abnormality) of an enzyme. In 1902 Archibald Garrod first attributed a disease to an enzyme defect: an inborn error of metabolism. Today, newborns are routinely screened for certain enzyme defects such as PKU (phenylketonuria) and galactosaemia, an error in the handling (metabolism) of the sugar galactose. (12 Dec 1998) |
| enzyme derepression | Removing or turning off the inhibitor or inhibitors (molecules which repress or prevent other molecules from acting) enzyme so that enzyme activity can resume. (09 Oct 1997) |
| enzyme electrode | A type of biosensor. An enzyme is immobilised on the surface of an electrode, and when the enzyme catalyses its reaction, electrons are transferred from the reactant to the electrode, and a current is generated, which can then be measured. (14 Nov 1997) |
| enzyme immobilisation | The attachment of an enzyme to a solid matrix so that it cannot escape but can still act on its substrate. (09 Oct 1997) |
| 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) |
| 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 inhibitors | Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction. (12 Dec 1998) |
| 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) |