5-Oxoprolinase deficiency

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. 

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... 

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