Copper(II) complexes of neuropeptide gamma with point mutations (S8,16A) products of metal-catalyzed oxidation.

To obtain the information about the influence of the serine residues (S8,S16) on the acid-base properties of the neuropeptide gamma, the peptide with point mutations (S8,16A) and its N-acetyl derivative were synthesized. Any additional deprotonations were not observed. It means that the presence of serine residues is necessary in the amino acid sequence of the neuropeptide gamma to have its acid-base properties.

Mono- and polynuclear copper(II) complexes of alloferons 1 with point mutations (H6A) and (H12A): stability structure and cytotoxicity.

Mononuclear and polynuclear copper(II) complexes of the alloferons 1 (Allo1) with point mutations (H6A) H(1)GVSGA(6)GQH(9)GVH(12)G-COOH (Allo6A) and (H12A) H(1)GVSGH(6)GQH(9)GVA(12)G-COOH (Allo12A) have been studied by potentiometric, UV-visible, CD, EPR spectroscopic, and mass spectrometry (MS) methods. Complete complex speciation at different metal-to-ligand ratios ranging from 1:1 to 3:1 was obtained. At physiological pH 7.

Copper(II) complexes of neurokinin A with point mutation (S5A) and products of copper-catalyzed oxidation; role of serine residue in peptides containing neurokinin A sequence.

A potentiometric, spectroscopic (UV-visible, CD and EPR) and electrospray ionization mass spectrometric (ESI-MS) study of Cu(II) binding to the neurokinin A with point mutation (S5A) (ANKA), His-Lys-Thr-Asp-Ala(5)-Phe-Val-Gly-Leu-Met-NH2 and its N-acethyl derivative (Ac-ANKA), Ac-His-Lys-Thr-Asp-Ala(5)-Phe-Val-Gly-Leu-Met-NH2 were carried out. For the ANKA and Ac-ANKA the additional deprotonation was not observed. It suggests that for the tachykinin peptides with C-terminal sequence of neurokinin A for the additional deprotonation the presence of the serine residue is necessary.

Acid-base properties of the (1-4,18-36) fragments of neuropeptide K and their mono- and polynuclear copper(II) complexes products of metal-catalyzed oxidation.

Mononuclear and polynuclear complexes of the (1-4,18-36)NPK, Asp(1)-Ala-Asp-Ser(4)-Gly(18)-His(19)-Gly-Gln-Ile-Ser-His(24)-Lys-Arg-His(27)-Lys-Thr-Asp-Ser-Phe-Val-Gly-Leu-Met(36)-NH(2), and mononuclear complexes of its acethyl derivative Ac-Asp(1)-Ala-Asp-Ser(4)-Gly(18)-His(19)-Gly-Gln-Ile-Ser-His(24)-Lys-Arg-His(27)-Lys-Thr-Asp-Ser-Phe-Val-Gly-Leu-Met(36)-NH(2) have been studied by potentiometric, UV-vis, CD, EPR spectroscopic, and mass spectrometry (MS) methods. As it was observed for other tachykinins (neurokinin A, neuropeptide gamma and its fragments) containing the same C-terminal sequence His-Lys-Thr-Asp-Ser-Phe-Val-Gly-Leu-Met-NH(2), also for the fragments of neuropeptide K the additional deprotonation most likely on the serine OH group was observed. It is likely that tachykinin peptides contain catalytic Ser/His/Asp triad or dyads Ser/Lys and the serine protease activity.