Globin chain turnover in reticulocytes from patients with β°‐thalassaemia/Hb E disease

Abstract

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 selective post‐translational catabolism. © Munksgaard 1995