Abstract
As part of an effort to develop peptide-based affinity labels for opioid receptors, [Leu5]enkephalin (LeuEnk) and DTLET (Tyr-D-Thr-Gly-Phe-Leu-Thr), potent agonists for δ receptors, were selected as the parent peptides for further modification. The affinity label derivatives were prepared using standard Fmoc solid-phase peptide synthesis in conjunction with Fmoc-Phe(p-NHAlloc) (Fmoc: 9-flourenylmethoxycarbonyl;) and selective modification of the p-amino group on this residue. The electrophilic isothiocyanate and bromoacetamide groups were introduced into the para position of Phe4; the corresponding free amine-containing peptides were also prepared for comparison. The pure peptides were evaluated in radioligand binding assays using Chinese hamster ovary (CHO) cells expressing δ and μ opioid receptors. Modification of Phe4 in LeuEnk and DTLET significantly decreased δ-receptor binding affinity (40 to >2,000-fold). Among the synthesized analogues, [Phe(p-NH2) 4]DTLET showed the highest δ-receptor binding affinity (IC 50 = 39 nM) and enhanced selectivity for δ receptors compared to DTLET while other derivatives exhibited much lower δ receptor affinity. The differences in affinities between the two series of analogues and between the derivatives of LeuEnk and N,N-dibenzyl[Leu5]Enk reported previously suggest subtle differences in interactions of Phe4 with δ receptors depending on other modifications in the sequences.
| Original language | English |
|---|---|
| Pages (from-to) | 552-557 |
| Number of pages | 6 |
| Journal | Biopolymers |
| Volume | 71 |
| Issue number | 5 |
| DOIs | |
| State | Published - 2003 |
| Externally published | Yes |
Fingerprint
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)
- Biochemistry
- Biophysics
Cite this
Synthesis and Evaluation of Derivatives of Leucine Enkephalin as Potential Affinity Labels for δ Opioid Receptors. / Choi, Heekyung; Murray, Thomas F.; Aldrich, Jane V.
In: Biopolymers, Vol. 71, No. 5, 2003, p. 552-557.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Synthesis and Evaluation of Derivatives of Leucine Enkephalin as Potential Affinity Labels for δ Opioid Receptors
AU - Choi, Heekyung
AU - Murray, Thomas F.
AU - Aldrich, Jane V.
PY - 2003
Y1 - 2003
N2 - As part of an effort to develop peptide-based affinity labels for opioid receptors, [Leu5]enkephalin (LeuEnk) and DTLET (Tyr-D-Thr-Gly-Phe-Leu-Thr), potent agonists for δ receptors, were selected as the parent peptides for further modification. The affinity label derivatives were prepared using standard Fmoc solid-phase peptide synthesis in conjunction with Fmoc-Phe(p-NHAlloc) (Fmoc: 9-flourenylmethoxycarbonyl;) and selective modification of the p-amino group on this residue. The electrophilic isothiocyanate and bromoacetamide groups were introduced into the para position of Phe4; the corresponding free amine-containing peptides were also prepared for comparison. The pure peptides were evaluated in radioligand binding assays using Chinese hamster ovary (CHO) cells expressing δ and μ opioid receptors. Modification of Phe4 in LeuEnk and DTLET significantly decreased δ-receptor binding affinity (40 to >2,000-fold). Among the synthesized analogues, [Phe(p-NH2) 4]DTLET showed the highest δ-receptor binding affinity (IC 50 = 39 nM) and enhanced selectivity for δ receptors compared to DTLET while other derivatives exhibited much lower δ receptor affinity. The differences in affinities between the two series of analogues and between the derivatives of LeuEnk and N,N-dibenzyl[Leu5]Enk reported previously suggest subtle differences in interactions of Phe4 with δ receptors depending on other modifications in the sequences.
AB - As part of an effort to develop peptide-based affinity labels for opioid receptors, [Leu5]enkephalin (LeuEnk) and DTLET (Tyr-D-Thr-Gly-Phe-Leu-Thr), potent agonists for δ receptors, were selected as the parent peptides for further modification. The affinity label derivatives were prepared using standard Fmoc solid-phase peptide synthesis in conjunction with Fmoc-Phe(p-NHAlloc) (Fmoc: 9-flourenylmethoxycarbonyl;) and selective modification of the p-amino group on this residue. The electrophilic isothiocyanate and bromoacetamide groups were introduced into the para position of Phe4; the corresponding free amine-containing peptides were also prepared for comparison. The pure peptides were evaluated in radioligand binding assays using Chinese hamster ovary (CHO) cells expressing δ and μ opioid receptors. Modification of Phe4 in LeuEnk and DTLET significantly decreased δ-receptor binding affinity (40 to >2,000-fold). Among the synthesized analogues, [Phe(p-NH2) 4]DTLET showed the highest δ-receptor binding affinity (IC 50 = 39 nM) and enhanced selectivity for δ receptors compared to DTLET while other derivatives exhibited much lower δ receptor affinity. The differences in affinities between the two series of analogues and between the derivatives of LeuEnk and N,N-dibenzyl[Leu5]Enk reported previously suggest subtle differences in interactions of Phe4 with δ receptors depending on other modifications in the sequences.
UR - http://www.scopus.com/inward/record.url?scp=0344305783&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0344305783&partnerID=8YFLogxK
U2 - 10.1002/bip.10533
DO - 10.1002/bip.10533
M3 - Article
VL - 71
SP - 552
EP - 557
JO - Biopolymers
JF - Biopolymers
SN - 0006-3525
IS - 5
ER -