| 3-mercaptolactate | A product of cysteine catabolism; formed by the action of lactate dehydrogenase on 3-mercaptopyruvate that was, in turn, formed by transamination of cysteine; present in normal human urine as a mixed disulfide with cysteine; elevated in the urine in individuals with mercaptolactate-cysteine disulfiduria. (05 Mar 2000) |
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| 3-mercaptopropionic acid | <chemical> 3-mercaptopropionic acid. An inhibitor of glutamate decarboxylase. It decreases the gaba concentration in the brain, thereby causing convulsions. Pharmacological action: convulsants, gaba agents, enzyme inhibitors. Chemical name: Propanoic acid, 3-mercapto- (12 Dec 1998) |
| 3-mercaptopyruvate | The transaminated product of cysteine; formed in cysteine catabolism; elevated in individuals with a deficiency of 3-mercaptopyruvate sulfurtransferase. 3-mercaptopyruvate sulfurtransferase, an enzyme that is a part of the cysteine catabolic pathway; it catalyses the conversion of 3-mercaptopyruvate to pyruvate and H2S; a deficiency of this enzyme will result in elevated urine concentrations of 3-mercaptopyruvate as well as of 3-mercaptolactate, both in the form of disulfides with cysteine. (05 Mar 2000) |
| 3-methoxy-4-hydroxymandelic acid | Misnomer for 4-hydroxy-3-methoxymandelic acid (a,3-dihydroxy-2-methoxybenzeneacetic acid);the major urinary metabolite of adrenal and sympathetic catecholamines (e.g., from both epinephrine and norepinephrine); elevated in most patients with pheochromocytoma. Acronym: VMA (05 Mar 2000) |
| 3-methoxy-4-hydroxymandelic acid test | A test for catecholamine-secreting tumours (pheochromocytoma and neuroblastoma) performed on a 24-hr urine specimen; it is based on the fact that vanillylmandelic acid is the major urinary metabolite of norepinephrine and epinephrine. Synonym: 3-methoxy-4-hydroxymandelic acid test, VMA test. (05 Mar 2000) |
| 3-methoxy-4-hydroxyphenylethanol | <chemical> 3-methoxy-4-hydroxyphenylethanol. Metabolite of serotonin and norepinephrine. Chemical name: Benzeneethanol, 4-hydroxy-3-methoxy- (12 Dec 1998) |
| 3-methyl-2-oxobutanoate hydroxymethyltransferase | <enzyme> Methylenetetrahydrofolate and alpha-ketoisovalerate gives tetrahydrofolate and ketopantoate Chemical name: 5,10-methylenetetrahydrofolate alpha-ketoisovalerate hydroxymethyltransferase Registry number: EC 2.1.2.11 Synonym: iphm transferase, panb protein, ketopantoate hydroxymethyltransferase (26 Jun 1999) |
| 3-methylbenzylalcohol dehydrogenase | <enzyme> Involved in m-xylene metabolism by pseudomomas paucimobilis Registry number: EC 1.1.1.- (26 Jun 1999) |
| 3-methylcholanthrene | A highly carcinogenic hydrocarbon that can be formed chemically from deoxycholic or cholic acids, or from cholesterol; the choice between 3-or 20-for the methyl group depends upon whether hydrocarbon (inner) or steroid (outer) numbering is chosen; in the latter case, the formal relationship to the cholic acids and cholesterol is clear. (05 Mar 2000) |
| 3-methylcrotonyl-CoA | (CH3)2C==CHCOSCoA;an intermediate in the degradation of l-leucine; accumulates in a deficiency of 3-methylcrotonyl-CoA carboxylase. 3-methylcrotonyl-CoA carboxylase, an enzyme in the pathway of l-leucine degradation that catalyses the reaction of 3-methylcrotonyl-CoA with CO2, ATP, and water to form ADP, orthophosphate, and 3-methylglutaconyl-CoA; a deficiency of this enzyme causes episodes of severe metabolic acidosis. (05 Mar 2000) |
| 3-methylglutaconic aciduria | Elevated levels of 3-methylglutaconic acid in the urine. An inherited disorder whose mild form is a result of a deficiency of 3-methylglutaconyl-CoA hydratase, leading to delayed speech development. (05 Mar 2000) |
| 3-methylglutaconyl-CoA hydratase | <enzyme> An enzyme that catalyses the reaction of trans-3-methylglutaconyl-CoA and water to form 3-hydroxy-3-methylglutaconyl-CoA; this enzyme participates in the pathway for l-leucine degradation; a deficiency of this enzyme will result in 3-methylglutaconic aciduria. (05 Mar 2000) |
| 3-methylitaconate delta-isomerase | <enzyme> Catalyses reversibly the isomerization of methylitaconate to dimethylmaleate Registry number: EC 5.3.3.6 Synonym: 3-midiase (26 Jun 1999) |