Restrictive hydrolysis of globin by citric acid

Restrictive hydrolysis of porcine globin by citric acid was investigated. The resulting hydrolyzate contained eight kinds of different peptides. After these peptides were separated from one another by tricine-SDS-PAGE system, the amino acid sequence of each peptide was partially determined. From these results, two kinds of peptides were presumed to be α-chain and β-chain of globin. Three in the remaining six kinds of peptides were derived from α-chain and the other peptides from β-chain. Citric acid specificially hydrolyzed the covalent bond between aspartic acid and proline residues of α-chain and β-chain of globin.