In molecular biology, ornatin is a potent glycoprotein IIb-IIIa (GP IIb-IIIa) antagonist and plateletaggregation inhibitor isolated from Placobdella ornata (Turtle leech).[1] The protein is 41-52 amino acids in length and contains the RGD recognition motif common in adhesion proteins, and 6 conservedcysteine residues. These form three disulphide bonds, which are required for activity.[2] The sequences of ornatin B, C, D and E are highly similar, while A2 and A3 are less similar, lacking the N-terminal 9 residues. Ornatins share ~40% identity with decorsin, a GP IIb-IIIa antagonist isolated from the leech (Macrobdella decora).[1]
^Mazur P, Dennis MS, Seymour JL, Lazarus RA (1993). "Expression, purification, and characterization of recombinant ornatin E, a potent glycoprotein IIb-IIIa antagonist". Protein Expr Purif. 4 (4): 282–9. doi:10.1006/prep.1993.1036. PMID8374297.
