BIIE0246: a selective and high affinity neuropeptide Y Y(2) receptor antagonist.

The in vitro biological characterisation of the first potent and selective non-peptide neuropeptide Y Y(2) receptor antagonist, (S)-N(2)-[[1-[2-[4-[(R,S)-5,11-dihydro-6(6h)-oxodibenz[b, e]azepin-11-yl]-1-piperazinyl]-2-oxoethyl] cylopentyl] acetyl]-N-[2-[1,2-dihydro-3,5(4H)-dioxo-1,2-diphenyl-3H-1,2, 4-triazol-4-yl]ethyl]-argininamid (BIIE0246) is reported. BIIE0246 displaced [125I]neuropeptide Y with high affinity (IC(50)=3.3 nM) from the human neuropeptide Y Y(2) receptor and proved to be highly selective.

The bioactive conformation of neuropeptide Y analogues at the human Y2-receptor.

Several attempts to investigate the bioactive conformation of neuropeptide Y have been made so far. As cyclic peptides are much more rigid than linear ones, we decided to synthesise cyclic analogues of the C-terminal dodekapeptide amide neuropeptide Y Ac-25-36. Cyclisation was performed by side chain lactamisation of ornithine or lysine and glutamic or aspartic acid.

Cleavage specificity on synthetic peptide substrates of human rhinovirus 2 proteinase 2A.

Proteinase 2A of human rhinovirus serotype 2 (HRV2 2A) was expressed in Escherichia coli and partially purified; the preparation was used to study various enzymatic parameters. Using a 16-amino acid peptide representing the native cleavage region of HRV2 2A, an apparent Km value of 5.4 x 10(-4) mol/liter was determined.

Further characterization of neuropeptide Y receptor subtypes using centrally truncated analogs of neuropeptide Y: evidence for subtype-differentiating effects on affinity and intrinsic efficacy.

Previous attempts to classify neuropeptide Y receptor subtypes suffered from relying only on carboxyl-terminal analogs and fragments of neuropeptide Y. We have tested the potency and affinity of chemically different compounds, i.e.

Cleavage kinetics and anchor linked intermediates in solid phase peptide amide synthesis.

Kinetics and cleavage conditions of peptide amide synthesis were studied using the anchor molecules 5-(4'-aminomethyl-3',5'-dimethoxyphenoxy)valeric acid (4-ADPV-OH) and 5-(2'-aminomethyl-3'-5'-dimethoxyphenoxy) valeric acid (2-ADPV-OH). Unexpectedly the anchor amide alanyl-4-ADPV-NH2 was isolated and characterized as an intermediate during the cleavage with trifluoroacetic acid (TFA) of alanyl-4-ADPV-alanyl-aminomethyl-polystyrene to yield the alanine amide. As a matter of fact the NH--CH alpha bond of the alanyl spacer has to be cleaved to form this intermediate.

Sulfonation of arginine residues as side reaction in Fmoc-peptide synthesis.

Several arginine-rich peptides containing the C-terminus of neuropeptide Y (NPY) were prepared by solid phase peptide synthesis using Fmoc chemistry and cleaved from the resin with trifluoroacetic acid (TFA). The products were characterized by fast atom bombardment-MS, LC-thermospray-MS, ion spray-MS/MS, and Edman degradation. The side products could be identified as peptides with sulfonated arginine residues resulting from an unexpected cleavage of Mtr or Pmc protecting groups.

Alpha-helical small molecular size analogues of neuropeptide Y: structure-activity relationships.

C-terminal analogues of neuropeptide Y (NPY) of small molecular size have been synthesized. The influence of chain length, single or multiple amino acid substitution, and segment substitutions on receptor binding, pre- and postsynaptic biological activity, and conformational properties have been investigated. Receptor binding and in vivo assays revealed biological activity for NPY Ac-25-36 that increased with increasing alpha-helicity.

Structure/activity relationships of C-terminal neuropeptide Y peptide segments and analogues composed of sequence 1-4 linked to 25-36.

C-terminal analogues of neuropeptide Y have been synthesized. The influence of chain length, single-amino-acid substitutions and segment substitutions on receptor binding, biological activity and conformational properties has been investigated. Receptor binding and in vivo assays revealed biological activity already for amino acids 28-36 of neuropeptide Y [neuropeptide Y-(Ac-28-36)-peptide] which increased with increasing chain length.

Neuropeptide Y: identification of the binding site.

Based on the hypothetical 3D structure of neuropeptide Y (NPY), NPY 1-4-Aca-25-36, a 17 amino acid analogue, has been synthesized replacing the sequence NPY 5-24 by epsilon-aminocaproic acid (Aca). This low-molecular weight deletion analogue showed nearly comparable receptor affinity to NPY. In order to elucidate the structural requirements for receptor recognition each amino acid of 1-4-Aca-25-36 was exchanged by its D-enantiomer, glycine and L-alanine.

Highly potent and small neuropeptide Y agonist obtained by linking NPY 1-4 via spacer to alpha-helical NPY 25-36.

Analogues of neuropeptide Y (NPY) containing small N- and C-terminal segments linked via flexible spacer arms were found to exhibit receptor binding affinity constants almost as high as NPY as well as post- and presynaptic NPY-agonistic activities. One of the most active analogues contains N-terminal NPY segment 1-4 linked via epsilon-aminocaproic acid (Aca) to the C-terminal partially alpha-helical peptide amide segment 25-36. NPY 1-4-Aca-25-36 is the first highly potent NPY agonist, which is of considerably reduced size in comparison to the native hormone.