Table 3.
Functional Bioactivities of H-Tyr/Dmt-Pro-Xaa-Phe-NH2 Endomorphin-2 Analogues
| no. | peptide | GPI assaya | MVD assaya | |||||
|---|---|---|---|---|---|---|---|---|
| IC50 (nM) | IC50 (nM)b | pA2c | ||||||
| 1 | Tyr-Pro-Phe-Phe-NH2 | 6.9 | ± | 0.9 | 344 | ± | 93 | |
| 1’ | Dmt-Pro-Phe-Phe-NH2d | 0.261 | ± | 0.038 | 0.59 | ± | 0.18 | |
| 2 | Tyr-Pro-Mmp-Phe-NH2 | 1.33 | ± | 0.27 | 15.7 | ± | 5.1 | |
| 2’ | Dmt-Pro-Mmp-Phe-NH2 | 0.162 | ± | 0.041 | >10000 (0.00%) | 6.59 | ||
| 3 | Tyr-Pro-3,5Dmp-Phe-NH2 | 389 | ± | 166 | >10000 (8.0%) | |||
| 3’ | Dmt-Pro-3,5Dmp-Phe-NH2 | 14.4 | ± | 5.4 | >10000 (7.1%) | 6.77 | ||
| 4 | Tyr-Pro-Dmp-Phe-NH2e | 0.378 | ± | 0.104 | 1.39 | ± | 0.17 | |
| 4’ | Dmt-Pro-Dmp-Phe-NH2 | 0.123 | ± | 0.020 | >10000 (15.6%) | 8.15 | ||
| 5 | Tyr-Pro-Dmt-Phe-NH2 | 541 | ± | 178 | 978 | ± | 113 | |
| 5’ | Dmt-Pro-Dmt-Phe-NH2 | 1.94 | ± | 0.21 | >10000 (<1%) | 7.06 | ||
| 6 | Tyr-Pro-Tmp-Phe-NH2 | 1.90 | ± | 0.49 | >10000 (36.2%) | |||
| 6’ | Dmt-Pro-Tmp-Phe-NH2 | 0.212 | ± | 0.077 | >10000 (22.2%) | 9.05 | ||
| 7 | Tyr-Pro-Emp-Phe-NH2 | 2.35 | ± | 0.53 | 277 | ± | 29 | |
| 7’ | Dmt-Pro-Emp-Phe-NH2 | 0.170 | ± | 0.072 | 0.51 | ± | 0.24 | |
| 8 | Tyr-Pro-Imp-Phe-NH2 | 2.74 | ± | 1.20 | >10000 (17.7%) | |||
| 8’ | Dmt-Pro-Imp-Phe-NH2 | 0.204 | ± | 0.050 | 5.56 | ± | 2.47 | |
The italicized compounds represent parental opioid peptides
a
The data are the means of over five independent repetitions used different isolated tissue preparations. IC50: concentration required for 50% inhibition of the electrically induced contraction in muscle derived from a dose-response curve.
b
Values in parentheses indicate maximal inhibition of the tissue contraction at the concentration of 10,000 nM.
c
Negative log of the molar concentration required to double the deltorphin II concentration to achieve the original response.
d
Data cited from ref. 29.
e
Data cited from ref. 34.