Sequence analysis of feline ferritin H and L subunit cDNAs

摘要

Feline ferritin H and L subunit cDNA clones were obtained using reverse transcriptase-polymerase chain reaction and TA cloning from feline leukocytes. Feline ferritin H and L subunit cDNA clones contained open reading frame sequences encoding 182- and174-amino acid proteins, respectively. The 7 amino acid residues associated with the ferroxidase center were perfectly conserved in the H subunit, and the 15 amino acid residues associated with the iron nucleation sites were perfectly conserved in the Lsubunit. Although amino acid sequence homology between feline H and L subunits was 52%, amino acid sequence homologies among mammalian H subunits was more than 91%, and those among mammalian L subunits was more than 84%, with the highest homology (H, 98%; L, 96%) being between feline and canine ferritin subunits. Sequence comparisons between feline and canine subunits showed 28 nucleotide substitutions and 2 amino acid replacements for the H subunit and 32 nucleotide substitutions and 7 amino acid replacements for the L subunit. Feline liver ferritin (L/H=2.5) produced the same response curve as canine liver ferritin (L/H=2.4) by sandwich ELISA using rabbit anti-rat liver ferritin antibodies. These results showed that feline ferritin is very similar in conformation as well as nucleotide sequence to canine ferritin.