Peptide | Designation | REC (Relative to SL-NH2)a | Ki, Binding | |
---|---|---|---|---|
Calcium | Binding | |||
μM | ||||
SLIGRL-NH2 | SL-NH2 | 1 | 1 | 0.26 |
Tc-LIGRLO-NH2 | tc-NH2 | 1.0 | 1.0 | 0.26 |
SLIGKV-NH2 | KV-NH2 | 2.1 | N.D. | N.D. |
SLIGR-NH2 | GR-NH2 | 4.0 | 8.9 | 2.3 |
SFLLR-NH2 | P5-NH2 | 2.8 | 8.9 | 2.3 |
SFLLRNP-NH2 | P7-NH2 | 14 | N.D. | N.D. |
SFLLRNP | P7 | 33 | N.D. | N.D. |
SFLLR | P5 | 72 | 120 | 85 |
TFLLR-NH2 | TF-NH2 | 220 | N.D. | N.D. |
The potencies of the PAR-APs relative to the activity of SL-NH2in the calcium signaling and binding competition assays (RECvalues) were determined essentially as outlined previously (Hollenberg et al., 1993, 1997), by using several points along the linear portions of the concentration-effect curves (Figs. 3-5; calcium signaling or binding competition) to estimate for each peptide an average concentration ratio (REC = ECPEPTIDE/ECSL-NH2) related to a concentration of SL-NH2 that caused the same effect (calcium signal; binding competition) as did the peptide studied. RECvalues greater than unity denote peptides that were lower in potency than SL-NH2. The Ki values for binding competition, calculated according to Cheng and Prusoff (1973), are also shown.
N.D., not determined. Values represent the average calculated from four or more points along the concentration-effect curves. PAR2-derived peptides are listed first, followed by the PAR1-derived peptides.