[Identification of hemoglobin D Punjab (beta 121 glu replaced by gln) in an Austrian family. Sequence analysis of the abnormal tryptic peptide beta XTp13].

In the course of a screening programme for gestational diabetes an abnormal haemoglobin fraction was detected by high-performance liquid chromatography (HPLC), used for Hb A1c-quantification. Cellulose acetate electrophoresis revealed a heterozygote haemoglobinopathy with approximately equal amounts of Hb A1 and of an abnormal haemoglobin which migrated in the position of Hb S under the conditions used. Preparative separation of these haemoglobin components was performed by use of a DEAE-cellulose column and standard conditions. alpha- and beta-chains were isolated with CM-sepharose and buffer containing 8M urea. The abnormal component of the aberrant haemoglobin was found to be the beta-chains in reconstitution experiments with globin-chains and haemin. A tryptic hydrolysate of the isolated abnormal beta-chains was analysed by means of HPLC and a C2 reverse phase (RP2). Rechromatography of the abnormal fractions on a C18 reverse phase (ODS) led to a pure preparation of peptide beta XTp13. The amino acid sequence analysis of this peptide showed an exchange of glutamic acid to glutamine in position beta 121 (beta 121 Glu----Gln). By these means evidence was obtained for the existence of a heterozygote Hb D Punjab state in the observed patient.