| gamma-glutamate (glutamate gamma-) carboxypeptidase | 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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| gene rearrangement, gamma-chain T-cell antigen receptor | Ordered rearrangement of T-cell variable gene regions coding for the gamma-chain of antigen receptors. (12 Dec 1998) |
| immunoglobulins, gamma-chain | Heavy chains found in the fab and fc fragments of IgG and having a molecular weight of approximately 51 kD. They contain about 450 amino acid residues arranged in four domains and an oligosaccharide component covalently bound to the fc fragment. The gamma chains of the four IgG subgroups are not identical, but resemble each other more closely than the heavy chains of a different immunoglobulin. (12 Dec 1998) |
| chain, orthodontic chain | <dentistry> A stretchable plastic chain used to hold archwires into brackets and to moke teeth. (08 Jan 1998) |
| alpha chain disease | A vague or indefinite term; could be used for alpha-heavy-chain disease (a lymphoplasma cell proliferative disease usually seen in Mediterranean men, characterised by intestinal involvement with steatorrhoea, often progressive with fatal outcome) or a thalassaemia (a genetic abnormality in the alpha globin chain of haemoglobin). (05 Mar 2000) |
| heavy chain disease | A disorder of immunoglobulin synthesis in which large quantities of abnormal heavy chains are excreted in the urine. The amino acid sequences of the n- (amino-) terminal regions of these chains are normal, but they have a deletion extending from part of the variable domain through the first domain of the constant region, so that they cannot form cross-links to the light chains. The defect arises through faulty coupling of the variable (v) and constant (c) region genes. (12 Dec 1998) |
| L-chain disease | bence Jones myeloma |
| bis-gamma-glutamylcystine reductase | <enzyme> From halobacterium halobium; specific for NADPH Registry number: EC 1.6.4.- Synonym: bis-ggc reductase (26 Jun 1999) |
| gamma | <physics> Third letter in the Greek alphabet, variable used for a number of things in physics, in plasma physics gamma is often used as the variable for growth rates of instabilities. (09 Oct 1997) |
| gamma-Abu | gamma-aminobutyric acid |
| gamma alcoholism | Jellinek's term for a severe stage of alcoholism characterised by a progression from psychological to physiological dependence upon alcohol, including tissue dependence and withdrawal symptoms, with loss of control over alcohol intake and destructive effects on interpersonal relationships. (05 Mar 2000) |
| gamma aminobutyric acid | <biochemistry> An important amino acid which functions as the most prevalent inhibitory neurotransmitter in the central nervous system. Gamma aminobutyric acid works in partnership with a derivative of Vitamin B-6, pyridoxine, to cross from the axons to the dendrites through the synaptic cleft, in response to an electrical signal in the neuron and inhibits message transmission. This helps control the nerve cells from firing too fast, which would overload the system. The action of gamma aminobutyric acid decreases epileptic seizures and muscle spasms by inhibiting electrical signals in this manner. Studies have shown that the site of action in the brain of benzodiazepams, including Valium, is directly coupled to the brain receptor for gamma aminobutyric acid. Acronym: GABA (05 Jan 1998) |
| gamma aminobutyric acid receptor | <physiology> Ligand gated chloride ion channel forming receptor opened by gamma aminobutyric acid. Two distinct types: A and B. A receptor: One of a family of neurotransmitter receptors with fast intrinsic ion channels that includes the glycine receptor and the nicotinic acetylcholine receptor. Distinct from another major receptor family, the muscarininc acetylcholine receptor and rhodopsin, with no intrinsic ion channel. The A receptor is specifically blocked by bicuculline. It consists of two pairs of protein chains forming an A2B2 complex, the A chains bind benzodiazepine and the B chains bind GABA. The 4 subunits are thought to form a tight group with the chloride channel in the middle. There is considerable similarity between the amino acid sequences of the receptor subunits and those of the nicotinic acetylcholine receptor suggesting that both receptors are derived from some evolutionary ancestor. See: amino acid receptor superfamily. B receptor: Brain receptor (80 kD) for the inhibitory neurotransmitter gamma amino butyric acid. Differs from the A receptor both in agonist specificity (baclofen is a specific agonist) and its effects on cells. It modulates intracellular calcium levels through a Go mediated effect on N type calcium channels and also lowers intracellular cAMP levels by an effect on adenylyl cyclase, thereby reducing the secretion of catecholamines. (05 Jan 1998) |
| gamma-amylase | A hydrolase removing terminal alpha-1,4-linked d-glucose residues from nonreducing ends of chains, with release of beta-d-glucose. Synonym: acid maltase, amyloglucosidase, gamma-amylase, glucoamylase. (05 Mar 2000) |
| gamma angle | <ophthalmology> The angle formed between a line joining the fixation point to the centre of the eye and the optic axis. (05 Mar 2000) |