Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Per cent stimulation of GR activity by FAD in vitro and PNP oxidase activity were measured in G6PD deficiency, heterozygous beta-thalassaemia and controls. It is confirmed that, in contrast to the high stimulation of GR by FAD commonly found in in thalassaemia indicating red-cell deficiency of FAD, and shown here to be greater in the Italian subjects, GR is usually saturated with FAD in G6PD deficiency, leading to high in vitro activity. Unexpectedly, on the other hand, low FMN-dependent PNP oxidase activity due to red-cell deficiency of FMN, confirmed by response to oral riboflavin, was found in the majority of subjects with G6PD deficiency, similar to that found in heterozygous beta-thalassaemia. Whereas this is explained in thalassaemia by an inherited slow red-cell metabolism of riboflavin to FMN, it is suggested that in G6PD deficiency an increased rate of red-cell metabolism of FMN to FAD leads to the low FMN and high FAD. When G6PD deficiency occurs with heterozygous beta-thalassaemia, GR is usually saturated with FAD as in G6PD deficiency alone, unless there is an inherited, very slow red-cell metabolism of riboflavin to FMN. The part played by GR in haemolytic crises in G6PD deficiency is discussed.
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PMID:Glutathione reductase activity and its relationship to pyridoxine phosphate activity in G6PD deficiency. 358 3

It was demonstrated in heterozygous alpha 1- and beta-thalassaemia, that the slow rate of red-cell metabolism of vitamin B6, previously shown to be inherited, is regulated by the FMN-dependent pyridoxine (pyridoxamine) phosphate oxidase, as in control subjects. In this study, 60% of the patients with thalassaemia had a low B6 oxidase activity. An inverse correlation with the stimulation of the FAD-dependent glutathione reductase activity by FAD confirmed that red-cell riboflavin status was responsible. The inherited nature and lack of signs of nutritional riboflavin deficiency led to the conclusion that this was the result of a slow rate of red-cell metabolism of riboflavin. Stimulation of glutathione reductase activity by FAD correlated inversely with its basic activity in thalassaemia and control subjects. There was a high incidence of a low activity of this enzyme per red cell in patients with thalassaemia. The possibility that a low activity of glutathione reductase and a slow metabolism of B6 and riboflavin in the red-cell might play a part in the degree of severity of the thalassaemic disease is discussed.
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PMID:Low red cell activity of pyridoxine (pyridoxamine) phosphate oxidase and glutathione reductase associated with thalassaemia. 733 97

In two areas in Italy where malaria was endemic--in the Po delta and Maremma on the west coast--we have found a high prevalence of an inherited flavin-deficient red cell in the normal population, suggesting selection by malaria. This study in Sardinia enabled a direct comparison of red-cell activities of FAD-dependent glutathione reductase (EGR) and FMN-dependent pyridoxine phosphate (PNP) oxidase in an ethnically homogeneous population, between two coastal villages where malaria was endemic from 300 B.C. and two mountain villages with no history of malaria. Both enzyme activities were significantly lower on the coast, and it did not seem that this could be explained by possible small differences in dietary riboflavin. As was thought to be the case in Ferrara and Grosseto, it is probable that a genetically controlled flavin-deficient red cell was selected for by malaria. Low EGR apoenzyme activity was more common on the coast, usually explaining the accompanying low basic EGR activity, and may also have been selected for by malaria. This adds to evidence from others that the mechanism of defence of a flavin-deficient red cell against malaria may be through EGR deficiency. It could also play a part in the protection given by heterozygous beta-thalassemia. The multifactorial protection of the population against malaria is discussed.
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PMID:Deficiency of two red-cell flavin enzymes in a population in Sardinia: was glutathione reductase deficiency specifically selected for by malaria? 766 97