Y-glutamyl transpeptidase deficiency

Harding, C. W., Williams, P, Wagner, E., Chang, D., Wild, K., Colwell, R., and Wolff, ]. (1997). Mice with genetic y-glutamyl transpeptidase deficiency exhibit glutathionuria, se% eregrowth failure, reduced lifespans, and infertility, f. Biol. Cficm. 272,12360-12567. 

LTC4-synthase deficiency 34.2 y-Glutamyl transpeptidase deficiency 34.3 Membrane-bound dipeptidase cystei nylg lyci nas e) deficiency... 

DNA analysis has not been performed yet. It might be in principle possible from genomic DNA (e.g. extracted from blood cells or cultured skin fibroblasts) in 31.1 (LTC4-synthase deficiency) and 34.3 (Membrane-bound dipeptidase deficiency). In 34.2 (y-Glutamyl transpeptidase deficiency) DNA analysis might be difficult since the human genome has at least seven different loco for y-glutamyl-transpeptidase. Five of them are located on chromosome 22. 

The significance of the y-glutamyl cycle is not fully understood. However, the finding of a mentally retarded individual who excretes 25-50 g / day of 5-oxoproline in the urine (possibly because of a defective 5-oxoprolinase) suggests that the pathway is a very active one.111 A few persons deficient in y-glutamyl transpeptidase have been found. They excrete glutathione and have a variety of medical problems.109... 

Oxoprolinase deficiency has been identified in eight patients, who lack a consistent clinical syndrome. Urinary excretion of 5-oxoproline is elevated but less than in glutathione synthetase deficiency. Erythrocytes contain an incomplete y-glutamyl cycle they lack both y-glutamyl transpeptidase and 5-oxoprolinase. 

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