Table 1.
Binding affinity of chromogranin A-derived peptides and A20FMDV2 for human and murine αvβ6 and αvβ8 integrin.
| Compound | Code | Ki b (competitive integrin binding assay) | ||||||
|---|---|---|---|---|---|---|---|---|
|
Free peptide a |
n c | Human αvβ6 (nM) |
n | Human αvβ8 (nM) |
||||
| CFETLRGEERILSILRHQNLLKELQD-CONH2 | 2a | 2 | >50000 d | 1 | >50000 d | |||
| ac-FETLRGDLRILSILRX1QNLX2KELQD-CONH2 | 5 | 7 | 0.6 ± 0.1 d | 6 | 3.2 ± 1.2 d | |||
| CFETLRGDLRILSILRX1QNLX2KELQD-CONH2 | 5a | 5 | 1.70 ± 0.26 | NAe | ||||
| CIRLDLELINFQSDLQHELLKTRLRG | 5a-Scr | 1 | >>200 | NA | ||||
| NAVPNLRGDLQVLAQKVART | A20FMDV2 | 8 | 0.9 ± 0.2 d | 6 | 69 ± 0.2 d | |||
| Peptide-NOTA conjugate | ||||||||
| 2a-NOTA | 1 | >>1000 | NA | |||||
| 5a-NOTA | 1 | 2.3 | NA | |||||
| EC50 f (direct integrin binding assay) | ||||||||
| αvβ6 | αvβ8 | |||||||
| Peptide-IRDye conjugate | n | Human (nM) |
n | Murine (nM) |
n | Human (nM) |
n | Murine (nM) |
| 2a-IRDye | 2 | >>100 | 3 | >>100 | 2 | >>100 | 3 | >>100 |
| 5a-IRDye | 2 | 2.8 ± 0.05 | 3 | 0.9 ± 0.35 | 2 | 1.9 ± 0.37 | 3 | 0.65 ± 0.50 |
| Cys-IRDye | 2 | >>100 | 3 | >>100 | 2 | >>100 | 3 | >>100 |
| 5a-Scr-IRDye | NA | NA | NA | NA | ||||
(a) Single letter code; triazole-stapled residues (X1 and X2, propargylglycine and azidolysine, respectively); ac-, N-terminal acetylated; -CONH2, C-terminal amidated. (b) Ki, inhibitory constant. Mean ± SE. (c) n, number of independent experiments. (d) Reprinted with the permission of Ref. 25. (e) NA, not analyzed. (f) EC50, Effective Concentration 50. Mean ± SE.