β°‐Thalassaemia/Hb E disease is the most frequent β‐thalassaemia in Thailand. However, patients have a varying degree of anaemia. The difference in severity is attributed to a differential accumulation of unpaired α‐globin chains, which is the net result of biosynthesis and catabolism. Turnover of newly synthesized globin chains in reticulocytes from β°‐thalassaemia/Hb E patients was determined. Proteolysis was ATP‐independent and degraded only 10–15 of the radiolabelled globin during a 4‐h incubation period at 37 °C and there was no difference in globin turnover in reticulocytes from subjects with mild and severe forms of β°‐thalassaemia/Hb E. These results indicate that excess α‐globin chains do not act as substrates for the reticulocyte proteolytic system and that the difference in severity of anaemia in β°‐thalassaemia/Hb E disease cannot be explained by a difference in selectiv
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