title: Low red cell activity of pyridoxine (pyridoxamine) phosphate oxidase and glutathione reductase associated with thalassaemia.
abstract: 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.
mesh_terms: D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology*; D005182:Flavin-Adenine Dinucleotide / Q000494:pharmacology; D005980:Glutathione Reductase / Q000097:blood*; D006801:Humans; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000097:blood*; D011734:Pyridoxaminephosphate Oxidase / Q000097:blood*; D011736:Pyridoxine / Q000097:blood; D012256:Riboflavin / Q000097:blood; D013789:Thalassemia / Q000201:enzymology*
chemical_list: D005182:Flavin-Adenine Dinucleotide; D011734:Pyridoxaminephosphate Oxidase; D000587:Oxidoreductases Acting on CH-NH Group Donors; D005980:Glutathione Reductase; D011736:Pyridoxine; D012256:Riboflavin