A single chain protein with an apparent molecular weight of 33 kDa was purified from skin of
Bombina maxima
by a combination of ion exchange and gel filtration chromatography steps. N-terminal amino acid sequence determination indicated that it shares 70%, 64% and 56% identity with those of annexin II from the African claw toad, red jungle fowl and human, respectively. The purified protein from
B. maxina inhibits stejnulxin (a specific platelet agonist via platelet membrane glycoprotein VI receptor) induced platelet aggregation in a Ca
2+ dependent manner. Maximal inhibition rate reaches 48%. Based on the N-terminal amino acid sequence BLAST search results and the fact that its activity is strictly Ca
2+ dependent, the purified protein might be structurally and functionally related to the annexin protein family.
