Leu-enkephalin amide

Fig. 12. Semipreparative separation of crude Leu-enkephalin amide O-benzyl ether (5) on a phenyl Porasil B column (60 x 0.7 cm) using a 30% acetonitrile-70% water-0.1% orthophosphoric acid isocratic mobile phase at a flow rate of 2 ml/min. The loading was 4 mg of peptide. Reprinted with permission from Hearn et al. (8). Copyright by Marcel Dekker, Inc., New York.

Fig. 11 Cluster plot of the first and second principal components derived by PCA from spectral data. The (5-receptor cluster covers DTLET, DSLET, DADLE, aLLeu -enkephalin, and DPDPE. The p-receptor cluster includes DAGO, MeC-enkephalin, and P-endorphin. The alternate (5-receptor cluster is composed of Leu -enkephalin and Leu -enkephalin amide. The K-cluster of the d5morphins contains B(l-13), A(l-13) A(l-9) A(l-ll) and A(l-13) amide. No receptor preference was reported for PLO 17 or ICI 174 864. (From Refs. ...

Release Profiles of Leu-enkephalin amide from Glu-containing Protein-based Polymers... 

Zero Order Release of Positively Charged Leu-enkephalin Amide from Negatively Charged Polymers... 

Leu-enkephalin amide (ff-Tyr-Gly-Gly-Phe-Leu-NHa, LEA ) is a positively charged opioid peptide from the endorphins that are so well known for causing the nmner s high. When added to a solution containing a rela-... 

Figure E.7. Controlled release of positively charged Leu-enkephalin amide (H -iyr-Gly-Gly-Phe-Leu-NH2, LEA ) from negatively charged polymers with systematically increased hydrophobicity with ApKa values of 0.9,1.3, and 2.2, giving AG.p values of 1.27, 1.84, and 3.12kcal/mole-E, respectively. Constant...

Other peptides with S-selectivity have also been reported (e.g., the hep-tapeptide[ Arg6, Phe7]-Met-enkephalin present in rat, bovine, and human brain in amounts comparable with those of Leu-enkephalin).<103) Among the most specific so far described is a dimeric tetrapeptide amide in which the monomer units (Tyr-D-Ala-Gly-Phe-NH) are linked by a 12-carbon chain.<104) The monomer itself shows /x-selectivity, but this changes to a preference for 5-receptors when two units are linked by a bimethylene chain 5-seleclivity increases as the length of the chain link increases and shows a dramatic rise when a 10-chain is replaced by a 12-chain link (Table 10.4). The dimer DTE12... 

A complete vibrational analysis has not been done for a type T j8-turn molecule, but the results of a Raman study of (Leu )-enkephalin (Han et al., 1980), which is known from X-ray diffraction analysis to form a type r turn (Smith and Griffin, 1978), are consistent with the predictions made for the standard turn. The dihedral angles in this molecule [(, i//)2 = 59°, 25° and (, //)3 = 97°, -7°] are quite close to the standard values of 60°, 30° and 90°, 0°, respectively, thus suggesting that the predictions for the standard type T turn (Table XXII) are likely to be applicable. Relevant amide I modes are calculated at 1684, 1680, 1676, and 1646... 

The primary structure of peptides (oligopeptides and polypeptides) is described as a linear sequence consisting of the 20 naturally occurring L-amino acids. These amino acids are linked together by amide bonds. Fig. 33 illustrates this for the pentapeptide Leu-enkephalin. 

Figure 231. The CPMG sequence performed on the pentapeptide Leu-enkephalin 2.2 in DMSO. Hie faster decay of the amide protons (left) relative to the aromatic protons of the tyrosine residue (right) results from the amide protons coupling to quadmpolar (Section 2.5). The very fast decay of the highest frequency amide proton occurs because this is in rapid chemical exchange with dissolved water, broadening the resonance significantly. The numbers show the total T2 relaxation period 2xn.

Figure 9.38. Release of positively charged Leu- release levels are maintained constant out to 3 enkephalin amide from designed, negatively charged months. Initial burst release due to 50% excess drug...

Temperature-dependent NMR, COSY, and NOESY experiments of the constrained Leu(5)-enkephalin amide analogue 16 containing a ferrocene substructure indicate an intramolecular hydrogen bond between Fc(l)CO and Fc(4)NH, creating a yS-turn structure [72]. The rotational barrier... 

Our group has prepared a number of [Leu Enkephalin derivatives with organometallic compounds attached to the N terminus via amide bond formation. In addition to the ferrocenoyl derivative 27 and the related cobaltocenium derivative 28 [61], we have also published the synthesis and characterization of two molybdenum derivatives 29 and 30 (see Schemes 5.13 and 5.14) [62]. In all cases, the enkephalin was prepared by standard solid phase peptide synthesis (SPPS) techniques the by Fmoc strategy. For compounds 27-29, the metal complex was attached to the deprotected N terminus of the peptide as the final step on the solid support. Subsequent cleavage from the resin was achieved by cone. NHj solution in MeOH (27 and 29) or cone. TFA (28), respectively, in accordance with... 

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