Six retro-inverso tri- and tetrapeptide analogues of RGD were prepared and
their anti-aggregatory activity was determined by platelet aggregation test
s in comparison with the corresponding parent peptides. An efficient method
for the introduction of a malonyl-aspartic residue into a peptide chain is
described for the first time. A 2-3-fold decrease in potency or total loss
of bioactivity was observed with the new peptides; structure-activity rela
tionships are discussed.