HB MELUSINE [ALPHA-114(GH2)PRO-]SER] - A NEW NEUTRAL HEMOGLOBIN-VARIANT

Hb Melusine [alpha114(GH2)Pro-->Ser] was found in an Algerian patient during a systematic screening for hemoglobinopathies performed in Luxe mbourg. The abnormal hemoglobin was suspected when a thickening of the Hb A band was observed by isoelectrofocusing. The mutant hemoglobin w as silent in all other electrophoretic methods used for presumptive di agnosis with the exception of globin electrophoresis in the presence o f Triton X-100. This technique revealed an alpha chain considerably mo re hydrophobic than normal. The structural abnormality of Hb Melusine concerns position alpha114(GH2) that belongs to a cluster of hydrophob ic residues localized in the N-terminal half of the alphaT-12b tryptic peptide. It has been shown in the case of another variant of that pos ition (Hb Nouakchott), that the replacement of the Pro GH2 by a Leu wa s responsible for a dramatic increase in the retention time of the alp ha polypeptide chain during reversed phase high performance liquid chr omatography, much higher than that reported for similar substitutions in other regions of the hemoglobin molecule.