In biochemistry, a method employed to determine differences in amino acid sequences between related proteins. The protein under study is enzymatically cleaved into a group of polypeptide fragments. These are separated in two dimensions: first by paper electrophoresis that separates peptides on the basis of net charge and second by partition chromatography that separates peptides on the basis of their degree of polarity (affinity for the hydrated cellulose support, which is highly polar). The result will be a two-dimensional array of spots, the “fingerprint.” This is compared to the standard fingerprint. The difference in the position of one spot in the case of the HbS and HbA fingerprints led to the discovery that the normal and mutant hemoglobins differed in a single amino acid substitution. See Chronology, 1957, Ingram; nucleic acid fingerprinting.
Subjects: Genetics and Genomics.