Sulphur amino-acid degradation in subjects with hereditary glutathione synthetase deficiency (5-oxoprolinuria).
The role of a low intracellular glutathione concentration in sulphur amino-acid degradation was investigated in two sisters (10 and 13 years old) with glutathione-synthetase deficiency, by determination of the urinary excretion of sulphur amino-acids and their main degradation products. The urinary excretion of total sulphur and inorganic sulphate was normal, indicating adequate dietary intake of sulphur amino-acids and normal oxidation to inorganic sulfate. Decreased excretion of N-acetylcysteine was found in the younger sister, which could be due to a reduced intracellular availability of cyst(e)ine. Increased excretion of mercaptolactate was found in the older sister, probably featuring a more catabolic condition in this subject. She also had an increased excretion of thiosulphate. Low excretion of thiocyanate was observed in both subjects, probably a consequence of a reduced dietary intake of thiocyanate or its precursors. Neither glutathione nor gamma-glutamylcysteine were detectable in urine. The excretion of cysteinylglycine was clearly reduced, reflecting that this dipeptide mainly is a degradation product of glutathione.
D000111:Acetylcysteine / Q000652:urine; D000293:Adolescent; D000603:Amino Acids, Sulfur / Q000378:metabolism*; D002648:Child; D004151:Dipeptides / Q000378:metabolism / Q000652:urine; D005260:Female; D005978:Glutathione / Q000378:metabolism; D005981:Glutathione Synthase / Q000172:deficiency* / Q000235:genetics; D006801:Humans; D010453:Peptide Synthases / Q000172:deficiency*; D011760:Pyrrolidinones / Q000652:urine*; D011761:Pyrrolidonecarboxylic Acid / Q000652:urine*; D013431:Sulfates / Q000652:urine
D000603:Amino Acids, Sulfur; D004151:Dipeptides; D011760:Pyrrolidinones; D013431:Sulfates; C028505:cysteinylglycine; D010453:Peptide Synthases; D005981:Glutathione Synthase; D005978:Glutathione; C017341:gamma-glutamylcysteine; D011761:Pyrrolidonecarboxylic Acid; D000111:Acetylcysteine