The GRGDS peptide contains the amino acid sequence Arg-Gly-Asp (RGD), which has been implicated as a recognition site in interactions between extracellular matrix (ECM) molecules and cell membrane receptors. RGD-containing synthetic peptides are known to inhibit attachment of endothelial cells to substrates. GRGDS peptide inhibits angiogenesis in serum-free collagen gel culture. This synthetic peptide mimics the cellular binding site of many adhesive proteins in the extracellular matrix and causes rounding and detachment of spread cells. This peptide is biotinylated through 6-aminohexanoate (LC) as a spacer.