Subunit structure of multiple hemoglobins in carp

Three hemoglobin components in carp designated CI, CII, and CIII, were isolated by DEAE-Tokyo-pearl ion-exchange chromatography. Constituent globin chains, alpha 1, alpha 2, beta 1, and beta 2, were analyzed by urea-Triton acid polyacrylamide gel electrophoresis and isolated by high performance liquid chromatography with a reverse-phase column. Tryptic peptide mapping indicated that the alpha-globin chains of the three hemoglobin components have slightly different structures. In addition, N-terminal amino acid sequence analysis indicated that the beta 1-globin chain has a primary structure different from that of the beta 2-chain. A series of hybridization experiments between isolated hemoglobins, together with such structural properties of globin chains, suggested that the three hemoglobins have the following compositions: CI (alpha 1 alpha 2 beta 1(2)), CII (alpha 1 alpha 2 beta 1 beta 2), and CIII (alpha 1 alpha 2 beta 2(2)). Hemoglobin CII was a hybrid between the two types each of alpha- and beta-chain and could be constructed in vitro from two hemoglobin components CI and CIII.