Plasma desorption mass spectrometry as a tool in characterization of abnormal proteins. Application to variant human hemoglobins.

We here report the application of plasma desorption mass spectrometry in combination with reversed-phase high-performance liquid chromatography and automatic Edman sequencing for the characterization of hemoglobin variants. By use of plasma desorption mass spectrometry to obtain molecular weight information of purified globin peptides it is possible to minimize the number of candidate positions for substitutions allowing an optimal use of automatic Edman degradation. Each variant can be characterized by using less than 200 micrograms of hemoglobin, corresponding to approximately 2 microliters of blood, as starting material. The outlined approach is considered to be very well suited for routine analysis of hemoglobins and other protein variants, natural as well as recombinant.