THE COVALENT COUPLING OF ARG-GLY-ASP-CONTAINING PEPTIDES TO LIPOSOMES- PURIFICATION AND BIOCHEMICAL FUNCTION OF THE LIPOPEPTIDE

With the advent of liposomes as drug carriers, there arises a need for efficient targeted delivery in vivo. Proteins coupled to liposomes us ually yield heterogeneous products that are ill-defined both chemicall y and in terms of spatial orientation. We now report on the disulfide linkage to the surface of intact liposomes of a peptide representing o ne-half of a ligand-receptor pair. An RGD-motif-containing peptide was coupled to the phospholipid PDP-DOPE of the liposomes by a thiol-disu lfide exchange. The resulting lipopeptides were amenable to definition by TLC, HPLC, and MS and found to be in a functional orientation allo wing biochemical interaction with their receptor, the integrin glycopr otein IIb-IIIa. (C) 1988 Academic Press.