Haptoglobin, a hemoglobin-binding plasma protein, is present in bony fish and mammals but not in frog and chicken.

ABSTRACT: Hemoglobin (Hb) released from erythrocytes may cause oxidation of lipids and proteins. Haptoglobin (Hp), which occurs in the plasma of all mammals, binds free Hb and inhibits its oxidative activity. It is not known whether this protective protein also exists in lower vertebrates. By analyzing available genomic sequences, we have found that bony fish, but not more primitive animals, have a gene coding for a protein homologous to mammalian Hp. Furthermore, we show that this protein is present in the plasma of Japanese pufferfish (Takifugu rubripes) and that it binds Hb. These results, together with a phylogenetic analysis, suggest that Hp evolved from a complement-associated protein (mannose-binding lectin-associated serine proteinase, MASP), with the emergence of fish. Surprisingly, we foun

SUBMITTER: Wicher KB 

PROVIDER: S-EPMC1449665 | biostudies-literature | 2006 Mar

REPOSITORIES: biostudies-literature