| induced 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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| interleukin-1 converting enzyme | <biochemistry> Cytoplasmic cysteine protease that is uniquely responsible for cleaving proIL-1_ (31 or 33 kD) into mature IL-1_ (17.5 kD), the active cytokine is then released by a nonstandard mechanism (there is no signal sequence and it does not pass through the Golgi). The enzyme seems to be composed of two nonidentical subunits derived from a single proenzyme. The ICE gene has some homology with the ced 9 gene of C. Elegans, the product of which is involved in mediating cell death by apoptosis. (11 Mar 1998) |
| intracellular enzyme | <enzyme> An enzyme that performs its functions within the cell that produces it; most enzyme's are intracellular enzyme's. Synonym: endoenzyme. (05 Mar 2000) |
| old yellow enzyme | <enzyme> A flavoprotein that reversibly oxidises NADPH to NADP and a reduced acceptor. Chemical name: NADPH:(acceptor) oxidoreductase Registry number: EC 1.6.99.1 (12 Dec 1998) |
| T enzyme | 1,4-alpha-d-glucan 6-alpha-d-glucosyltransferase. (05 Mar 2000) |
| terminal addition enzyme | <enzyme> A non-template-directed DNA polymerase normally found in vertebrate thymus and bone marrow. It catalyses the elongation of oligo- or polydeoxynucleotide chains and is widely used as a tool in the differential diagnosis of acute leukaemias in man. Chemical name: Nucleoside-triphosphate:DNA deoxynucleotidylexotransferase Registry number: EC 2.7.7.31 (12 Dec 1998) |
| thermostable enzyme | <enzyme> An enzyme that is not readily subject to destruction or alteration by heat. Synonym: heat-stable enzyme. (05 Mar 2000) |
| thiol enzyme | <enzyme> An enzyme whose activity depends on a free thiol group. (05 Mar 2000) |
| ecori restriction enzyme | <enzyme, molecular biology> A commonly-used restriction enzyme (enzyme which will cleave the phosphodiester bonds of DNA at specific nucleotide sequences) that came from the bacteria Escherichia coli and recognises the sequence GAATTC. The enzyme will make a staggered cut of the double-stranded DNA molecule by cutting between the G and A on both strands. (09 Oct 1997) |
| enzyme | <biochemistry> A protein molecule produced by living organisms that catalyses chemical reactions of other substances without itself being destroyed or altered upon completion of the reactions. Enzymes are classified according to the recommendations of the Nomenclature Committee of the International Union of Biochemistry. Each enzyme is assigned a recommended name and an Enzyme Commission (EC) number. They are divided into six main groups, oxidoreductases, transferases, hydrolases, lyases, isomerases and ligases. (09 Oct 1997) |
| enzyme activation | Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1) activation by ions (activators); 2) activation by cofactors (coenzymes); and 3) conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme. (12 Dec 1998) |
| enzyme analog | A synthetic macromolecule having enzymatic activity. Synonym: enzyme analog. (05 Mar 2000) |
| enzyme antagonist | An antimetabolite or inhibitor of enzyme action. (05 Mar 2000) |
| 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) |
| 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) |