GLOBIN CHAIN TURNOVER IN RETICULOCYTES FROM PATIENTS WITH BETA(O)-THALASSAEMIA HB-E DISEASE/

beta degrees-Thalassaemia/Hb E. disease is the most frequent beta-thal assaemia in Thailand. However, patients have a varying degree of anaem ia. The difference in severity is attributed to a differential accumul ation of unpaired alpha-globin chains, which is the net result of bios ynthesis and catabolism. Turnover of newly synthesized globin chains i n reticulocytes from beta degrees-thalassaemia/Hb E patients was deter mined. Proteolysis was ATP-independent and degraded only 10-15% of the radiolabelled globin during a 4-h incubation period at 37 degrees C a nd there was no difference in globin turnover in reticulocytes from su bjects with mild and severe forms of beta degrees-thalassaemia/Hb E. T hese results indicate that excess alpha-globin chains do not act as su bstrates for the reticulocyte proteolytic system and that the differen ce in severity of anaemia in beta degrees-thalassaemia/Hb E disease ca nnot be explained by a difference in selective post-translational cata bolism.