Electrophoretic Methods for Study of Hemoglobins

Electrophoresis, a technique consisting of the migration of electrically charged molecules under an applied electric field, occupies one of the most important places in the history of the study of hemoglobin (Hb). HbS, the first abnormal Hb described, was discovered in 1949 by Pauling et al. (1 ), using moving boundary electrophoresis. Later, Hb variants were detected by zone electrophoresis on paper, starch gel, or cellulose acetate (2 ,3 ). With the exception of cellulose acetate electrophoresis, which is still used in some laboratories, these procedures have been replaced by isoelectric focusing (IEF) (4 ). In IEF, a pH gradient is established by carrier ampholytes subjected to an electric current. The Hb molecule migrates across this gradient until it reaches the position where its net charge is zero (isoelectric point [pI]). It then concentrates into a sharp band.