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Table 2 Binding affinities and receptor selectivities for Dmt-Tic and Tyr-Tic peptides

From: δ Opioidmimetic Antagonists: Prototypes for Designing a New Generation of Ultraselective Opioid Peptides

   

Ki (nM)

 

Peptide

R

R

δ

μ

μδ

Dipeptides

1. Dmt-Tic

OH

 

0.022 ± 0.0015 (6)

3,317 ± 435 (7)

150,773

2. Dmt-Tic

NH2

 

1.22 ± 0.09 (6)

276.8 ± 26.9 (3)

227

3. Dmt-d-Tic

OH

 

13.5 ± 1.59 (4)

224.4 ± 25.6 (3)

17

4. Dmt-d-Tic

NH2

 

56.9 ± 2.90 (3)

3.8 ± 0.24 (3)

0.067

5. Dmt-Tic

CH2OH

 

0.44 ± 0.14 (6)

151.4 ± 16.3 (3)

344

6. Tyr-Tic

OH

 

191.7 ± 47.8 (7)

28,411 ± 2,941 (3)

148

7. Tyr-Tic

NH2

 

165.9 ± 48.1 (4)

28,712 ± 3,305 (7)

173a

8. Tyr-d-Tic

OH

 

9,046 ± 719 (5)

26,258 ± 427 (3)

2.9

9. Tyr-d-Tic

NH2

 

5,959 ± 981 (4)

3,135 ± 491 (4)

0.53a

10. Tyr-Tic

CH2OH

 

128.1 ± 34.7 (4)

11,003 ± 1,851 (3)

86

Tripeptides

11. Dmt-Tic

Ala

OH

0.285 ± 0.03 (6)

5,813 ± 675 (4)

20,396

12. Dmt-Tic

Ala

NH2

0.241 ± 0.02 (5)

47.1 ± 3.4 (4)

195

13. Dmt-d-Tic

Ala

OH

88.7 ± 13.8 (5)

82.8 ± 2.0 (3)

0.93

14. Dmt-d-Tic

Ala

NH2

46.4 ± 2.7 (3)

5.8 ± 0.85 (4)

0.13

15. Tyr-Tic

Ala

OH

56.1 ± 10.3 (3)

8,291 ± 1,377 (3)

148a

16. Tyr-Tic

Ala

NH2

55.5 ± 13.7 (3)

33,844 ± 1,405 (3)

610a

17. Tyr-d-Tic

Ala

OH

2,346 ± 356 (3)

14,028 ± 2,166 (3)

6

18. Tyr-d-Tic

Ala

NH2

21,076 ± 4,427 (3)

8,146 ± 1,377 (3)

0.39a

  1. Ki, affinity constant; Kiμ/Kiδ, ratio of affinities, i.e., selectivity for δ receptors relative to μ receptors.
  2. aThese binding data were published in Temussi et al. (18) and are included for a comprehensive comparison to the Dmt-Tic analogs.