Location of amino acid substitutions in human hemoglobin. Mass spectrometric rapid analysis of tryptic peptides

: Point mutations alpha 58 His----Tyr (Hb M Boston), beta 6 Glu--lys (Hb C) and beta 26 Glu----Lys (Hb E) have been identified in abnormal hemoglobins by means of tryptic hydrolysis of their alpha- and beta-chains followed by mass-spectrometry coupled with direct extraction of ions from solution. The abnormal hemoglobin Hb M Boston alpha 58 (E7) His----Tyr has been for the first time found in the blood of a patient from the USSR. This express-method is generally applicable for the identification of point mutation in proteins. The amount of protein necessary for the analysis is 100-1000 pmole. The stability, proteolytic degradation of the identified abnormal Hb's and Hb Bart's were investigated. The molecular pathogenesis of the hemoglobinopathies are discussed from the point of view of the observed properties.