The peptides APLHK, EHIPA and GAPL are hydropathically equivalent peptide mimics of a fibrinogen binding domain of glycoprotein IIb/IIIa.

The anticomplementarity hypothesis predicted that the peptides APLHK, EHIPA, GAPL and LGVPPR would be functional mimics of a fibrinogen binding domain(s) in the fibrinogen receptor. The peptides APLHK and EHIPA were derived by translation of the cRNA of vitronectin m-RNA. The peptides GAPL and LGVPPR result from translations of the cRNA of von Willebrand factor m-RNA. The peptides APLHK, EHIPA, and GAPL, but not LGVPPRT, are hydropathically equivalent and inhibit fibrinogen binding to platelets. APLHK and EHIPA are hydropathic retromers. Thus for one pair of these peptides, the direction of their backbones did not affect function.