| gamma-glutamyl hydrolase | N-Pteroyl-l-glutamate hydrolase;an enzyme cleaving l-glutamyl residues from pteridine oligoglutamates; used in certain antitumour treatments. Synonym: carboxypeptidase G, conjugase, gamma-glutamate (glutamate gamma-) carboxypeptidase. (05 Mar 2000) |
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| gamma-glutamyltransferase | <enzyme> An enzyme that catalyses reversibly the transfer of a glutamyl group from a glutamyl-peptide and an amino acid to a peptide and a glutamyl-amino acid. It is often elevated above normal in hepatitis and other conditions that cause chemical liver damage. Chemical name: (5-L-Glutamyl)-peptide:amino-acid 5-glutamyltransferase Registry number: EC 2.3.2.2 Acronym: GGT (12 Sep 2002) |
| gamma-glutamyl transpeptidase | <enzyme> An enzyme that catalyses reversibly the transfer of a glutamyl group from a glutamyl-peptide and an amino acid to a peptide and a glutamyl-amino acid. It is often elevated above normal in hepatitis and other conditions that cause chemical liver damage. Chemical name: (5-L-Glutamyl)-peptide:amino-acid 5-glutamyltransferase Registry number: EC 2.3.2.2 Acronym: GGT (12 Sep 2002) |
| gamma-guanidinobutyraldehyde dehydrogenase | <enzyme> Nad and gamma-guanidinobutyraldehyde yields gamma-guanidinibutyrate and NADH Registry number: EC 1.2.1.- (26 Jun 1999) |
| gamma-iodopropyleneglycol | An organic form of iodine which slowly liberates iodine in the body after oral administration. Used primarily as an expectorant/mucolytic. Synonym: 3-iodo-1,2-propanediol, gamma-iodopropyleneglycol. (05 Mar 2000) |
| gamma knife | <radiobiology> A special multi-source irradiation machine which focus a high intesity of irradiation on a small area: it is used as local therapy in especially brain tumours. This is investigational and is not part of the routine array of cancer treatments. (16 Dec 1997) |
| gamma-l-glutamyl-l-cysteinylglycine | <biochemistry> The tripeptide _ glutamylcysteinylglycine. It contains an unusual peptide linkage between the _ carboxyl group of the glutamate side chain and the amine group of cysteine. The concentration of glutathione in animal cells is _5mM and its sulphydryl group is kept largely in the reduced state. This allows it to act as a sulphydryl buffer, reducing any disulphide bonds formed within cytoplasmic proteins to cysteines. Hence, few, if any, cytoplasmic proteins contain disulphide bonds. Glutathione is also important as a cofactor for the enzyme glutathione peroxidase, in the uptake of amino acids and participates in leucotriene synthesis. (18 Nov 1997) |
| gamma-linolenic acid | <chemical> (z,z,z)-6,9,12-octadecatrienoic acid. An omega-6 fatty acid produced in the body as the delta 6-desaturase metabolite of linoleic acid. It is converted to dihomo-gamma-linolenic acid, a biosynthetic precursor of monoenoic prostaglandins such as pge1. Chemical name: 6,9,12-Octadecatrienoic acid, (Z,Z,Z)- (12 Dec 1998) |
| gamma loop | The reflex arc consisting of small anterior horn cells and neuroma, their small fibres projecting to the intrafusal bundle producing its contraction, which initiates the afferent impulses that pass through the posterior root to the anterior horn cells, inducing a stretch reflex. Synonym: gamma motor neurons, gamma motor system, Granit's loop. (05 Mar 2000) |
| gamma motor neurons | The reflex arc consisting of small anterior horn cells and neuroma, their small fibres projecting to the intrafusal bundle producing its contraction, which initiates the afferent impulses that pass through the posterior root to the anterior horn cells, inducing a stretch reflex. Synonym: gamma motor neurons, gamma motor system, Granit's loop. (05 Mar 2000) |
| gamma motor system | The reflex arc consisting of small anterior horn cells and neuroma, their small fibres projecting to the intrafusal bundle producing its contraction, which initiates the afferent impulses that pass through the posterior root to the anterior horn cells, inducing a stretch reflex. Synonym: gamma motor neurons, gamma motor system, Granit's loop. (05 Mar 2000) |
| gamma-oxalomesaconate hydratase | <enzyme> From pseudomonas ochraceae; forms gamma-oxalocitramalate Registry number: EC 4.2.1.- Synonym: gom hydratase (26 Jun 1999) |
| gamma radiation | Ionizing electromagnetic radiation resulting from nuclear processes, such as radioactive decay or fission. (05 Mar 2000) |
| gamma ray | <radiobiology> Electromagnetic radiation (photons) with energies greater than (roughly) 100 keV (that is, 100,000 electron volts). Gamma radiation frequently accompanies alpha and beta decays, and always accompanies fission. Gamma rays are highly penetrating and are best shielded against using dense materials, such as lead or depleted uranium. (Gamma rays are similar to X-rays, but are generally higher in energy and nuclear in origin.) Gamma rays have wavelengths of 1 nanometre or shorter. These are highly energised, deeply penetrating photons which can be emitted from an atomic nucleus during nuclear fission (the splitting of an atom) and during regular atomic decay (radioactivity). (13 Oct 1997) |
| gamma ray knife | A beam of high energy X-rays. See: radiosurgery. (05 Mar 2000) |