Table 1.
Binding affinity assays and biological assays of penicillamine-containing cyclic enkephalins
| Compound | Binding affinity assays | Biological assays | ||
|---|---|---|---|---|
| vs[3H]DADLE δ (nM) |
vs[3H]naloxone μ (nM) |
MVD (nM) |
GPI (nM) | |
| c[D-Pen2,Cys5]enka | 11.7 | 178 | 0.32 | 213 |
| c[D-Pen2,D-Cys]enka | 26 | 157 | 6.3 | 1,350 |
| c[D-Pen2,Cys5]enk-NH2a | 3.4 | 73 | 3.6 | 118 |
| c[D-Pen2,D-Cys5]enk-NH2a | 7.2 | 162 | 16.8 | 117 |
| c[D-Pen2,D-Pen5]enk (DPDPE) | 1.6 | 610 | 4.1 | 7,300 |
| [2S,3S]TMT1-DPDPE | 211 | 720 | 170 | 290 |
| [2S,3R]TMT1-DPDPE | 5.0 | 4,300 | 1.8 | 0% at 60 μM (antagonist) |
| [2R,3S]TMT1-DPDPE | 9% at 10 μM | 0% at 10 μM | 28% at 10 μM | 75% at 10 μM |
| [2R,3R]TMT1-DPDPE | 3,500 | 77,000 | 2,200 | 75% at 82 μM |
a
Data taken from Reference 29.
Abbreviations: DADLE, [D-Ala2,D-Leu5]enkephalin; DPDPE, c[D-Pen2,D-Pen5]enkephalin; enk, enkephalin; GPI, guinea pig ileum; MVD, mouse vas deferens; TMT, β-methyl-2′,6′-dimethyltyrosine (trimethyltyrosine).