| tryptophan decarboxylase | <enzyme> An enzyme that catalyses the decarboxylation of l-dopa to dopamine, of l-tryptophan to tryptamine, and of l-hydroxytryptophan to serotonin; important in the biosynthetic pathway of catecholamines and melanin. Synonym: dopa decarboxylase, hydroxytryptophan decarboxylase, tryptophan decarboxylase. (05 Mar 2000) |
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| tryptophan desmolase | <enzyme> An enzyme that catalyses the conversion of l-serine and 1-(indol-3-yl)glycerol 3-phosphate to l-tryptophan and glyceraldehyde 3-phosphate. It is a pyridoxal phosphate protein that also catalyses the conversion of serine and indole into tryptophan and water and of indoleglycerol phosphate into indole and glyceraldehyde phosphate. Chemical name: L-Serine hydro-lyase (adding indoleglycerol-phosphate) Registry number: EC 4.2.1.20 (12 Dec 1998) |
| tryptophan hydroxylase | <enzyme> An enzyme that catalyses the hydroxylation of tryptophan to 5-hydroxytryptophan in the presence of NADPH and molecular oxygen. It is important in the biosynthesis of serotonin. Chemical name: L-tryptophan,tetrahydropteridine:oxygen oxidoreductase (5-hydroxylating) Registry number: EC 1.14.16.4 (12 Dec 1998) |
| tryptophan oxygenase | <enzyme> A protohemoprotein. Forms formylkynurenine from l-tryptophan and molecular oxygen. Chemical name: L-Tryptophan:oxygen 2,3-oxidoreductase (decyclizing) Registry number: EC 1.13.11.11 (12 Dec 1998) |
| tryptophan pyrrolase | An oxidoreductase catalyzing the reaction of l-tryptophan and O2 to produce l-N-formylkynurenine; an adaptive enzyme, the level (in the liver) being controlled by adrenal hormones; a step in tryptophan catabolism; also, a step in the synthesis of NAD+ from tryptophan. Synonym: pyrrolase, tryptophan oxygenase, tryptophan pyrrolase, tryptophanase. (05 Mar 2000) |
| tryptophan synthase | <enzyme> An enzyme that catalyses the conversion of l-serine and 1-(indol-3-yl)glycerol 3-phosphate to l-tryptophan and glyceraldehyde 3-phosphate. It is a pyridoxal phosphate protein that also catalyses the conversion of serine and indole into tryptophan and water and of indoleglycerol phosphate into indole and glyceraldehyde phosphate. Chemical name: L-Serine hydro-lyase (adding indoleglycerol-phosphate) Registry number: EC 4.2.1.20 (12 Dec 1998) |
| tryptophan synthetase | <enzyme> An enzyme that catalyses the conversion of l-serine and 1-(indol-3-yl)glycerol 3-phosphate to l-tryptophan and glyceraldehyde 3-phosphate. It is a pyridoxal phosphate protein that also catalyses the conversion of serine and indole into tryptophan and water and of indoleglycerol phosphate into indole and glyceraldehyde phosphate. Chemical name: L-Serine hydro-lyase (adding indoleglycerol-phosphate) Registry number: EC 4.2.1.20 (12 Dec 1998) |
| tryptophan-trna ligase | <enzyme> An enzyme that activates tryptophan with its specific transfer RNA. Chemical name: L-Tryptophan:tRNA(Trp) ligase (AMP-forming) Registry number: EC 6.1.1.2 (12 Dec 1998) |
| 4-(4'-hydroxy-3'-methylbut-2'-enyl)-L-tryptophan synthetase | <enzyme> Enzymatic synthesis of above cpd from isopentenylpyrophosphate and tryptophan Registry number: EC 6.- (26 Jun 1999) |
| L-tryptophan 2',3'-oxidase | <enzyme> Specifically catalyses the alpha,beta-dehydrogenation of l- tryptophan derivatives; from chromobacterium violaceum Registry number: EC 1.3.99.- Synonym: l-tryptophan - oxygen 2',3'-oxidoreductase, l-trp-2',3'-oxidase (26 Jun 1999) |
| Abbe test plate | <equipment> A long, wedge-shaped coverslip about 0.20 mm thick at one end and 0.10 to 0.12 mm at the other end coated chemically with a silver film on which are ruled horizontal lines. at each variation in thickness of 0.01 mm there are vertical lines. By means of oblique illumination and by focusing on different portions of the plate, it is possible to determine the optimum coverslip thickness for any objective and also, for microscopes with drawtubes, the tube length for best objective performance. The approximate freedom from spherical and chromatic aberrations can also be estimated. Small isolated bits of silver near the edges of the lines form good objects for the star test (05 Aug 1998) |
| acetone test | A test for ketonuria; the suspected urine is shaken up with a few drops of sodium nitroprusside, and strong ammonia water is then gently poured over the mixture; if acetone is present, a magenta ring forms at the line of contact; tablets containing sodium nitroprusside and alkali are now more commonly used. (05 Mar 2000) |
| achievement test | A standardised test used to measure acquired learning, e.g., competence in a specific subject area such as reading or arithmetic, in contrast to an intelligence test which is a useful index of potential ability or learning. (05 Mar 2000) |
| acidified serum test | Lysis of the patient's red cells in acidified fresh serum, specific for paroxysmal nocturnal haemoglobinuria. Synonym: Ham's test. (05 Mar 2000) |
| acid loading test | <nephrology> This is a test used in the diagnosis of renal tubular acidosis. The patient takes ammonium chloride capsules for 3 days to acidify the blood (lower blood pH). A sample of the urine and the blood is then collected and the results are interpreted. (27 Sep 1997) |