TABLE 2.

Binding of linear and cyclic isoDGR peptides (acetylated and not acetylated) to integrins as measured by competitive binding assay

Competitor	Binding of ac-isoDGR/STV-HRP to
	αvβ3		αvβ5		αvβ6		αvβ8		α5β1
	na	Kib	n	Ki	n	Ki	n	Ki	n	Ki
		nm		nm		nm		nm		nm
isoDGR-2C	6	9 ± 2	6	380 ± 108	6	118 ± 39	4	710 ± 68	4	95 ± 33f
ac-isoDGR-2C	5	2 ± 0.4c	5	29 ± 7	4	5 ± 2	3	22 ± 6	3	6 ± 2
isoDGR-2G	3	1086 ± 186d	3	6138 ± 1756	3	256 ± 52	3	7370 ± 820	3	1489 ± 424
ac-isoDGR-2G	3	254 ± 81e	3	845 ± 65	3	163 ± 26	3	878 ± 71	3	226 ± 39

^a n, number of independent experiments (each in duplicate).

^b K_i: equilibrium dissociation constant of the competitor (mean ± S.E.). K_i was calculated by nonlinear regression analysis of competitive binding data by using the “One site-Fit K_i” equation of the GraphPad Prism Software (GraphPad Software, Version 5.00 San Diego, CA).

^c p < 0.05 (ac-isoDGR-2C versus isoDGR-2C).

^d p < 0.05 (isoDGR-2G versus isoDGR-2C).

^e p < 0.01 (ac-isoDGR-2G versus ac-isoDGR-2C).

^f p < 0.05 (α5β1 versus αvβ3).