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Chromium(III) complexes with DL-methionine and L-cysteine

100%

Masłowska J., Chruściński L., University P.

Acta Universitatis Lodziensis. Folia Chimica

1984

vol. 3

Chromium(III) complexes with DL-methionine and L-cysteine have beon investigated by pH-metric and spectrophotometric methods. In both investigated systems, three complexes of the composition H : L = 1 : 1; 1 : 2; 1 : 3, have been found, stability constants for the resultant complexes have been determined by the method of Bjerrum. Crystalline complexes with the investigated ligands of the type: [Cr(Met)₃]. 2H₂O and Na[Cr(Cys)₂]. 2H₂O were also obtained. The made combination of Cr(III) with the investigated aminoacid and structures of the complexes reported have been proposed on the basis of their spectra. A method for precipitation pure complexes from solutions has been devised using the ion-exchange procese on the resin Sephadex A-25.

Chelating ability of proctolin tetrazole analogue

61%

Łodyga-Chruścińska E., Sanna D., Micera G., Chruściński L., Olejnik J., Nachman R. J., Zabrocki J.

2006

vol. 53

issue 1

65-72

The aim of the investigation was to establish the chelating ability of a new proctolin analogue of the sequence Arg-Tyr-LeuΨ[CN4]Ala-Thr towards copper(II) ions. The insertion of the tetrazole moiety into the peptide sequence has considerably changed the coordination ability of the ligand. Potentiometric and spectroscopic (UV-Vis, CD, EPR) results indicate that the incorporation of 1,5-disubstituted tetrazole ring favours the formation of a stable complex form of CuH-1L. This 4N coordination type complex is the dominant species in the physiological pH range. The tetrazole moiety provides one of these nitrogens. The data indicate that Cu(II) ions are strongly trapped inside the peptide backbone. These findings suggest that Cu(II) can hold peptide chains in a bent conformation. This bent conformation may be essential for bioactivity of the tetrazole peptides.

Effect of tetrazole moiety on coordinating efficiency of deltorphin.

61%

Łodyga-Chruścińska E., Ołdziej S., Micera G., Sanna D., Chruściński L., Olczak J., Zabrocki J.

vol. 51

issue 1

93-106

A study of the effect of the tetrazole moiety, a cis-amide bond surrogate, on the Cu(II) coordinating properties of oligopeptides is reported. Insertion of the tetrazole moiety Ψ[CN4] into the peptide sequence of [D-Ala2]deltorphin I changes considerably the coordination ability of the peptide. Potentiometric and spectroscopic results show that if the tetrazole moiety is in a suitable position in the peptide chain, i.e. it follows the second residue, a stable CuL species involving 3N coordination is formed in the physiological pH range. The tetrazole Ψ[CN4] ring provides one of these nitrogens. The data indicate that Cu(II) ions are strongly trapped inside a bent peptide backbone. The peptide conformation changes achieved by Cu(II) coordination may be essential for the binding of tetrazole deltorphins at opiate receptors.

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2 Acta Biochimica Polonica

1 Acta Universitatis Lodziensis. Folia Chimica

1 2006

1 2004

1 1984

3 Chruściński L.

2 Micera G.

2 Sanna D.

2 Zabrocki J.

2 Łodyga-Chruścińska E.

1 Masłowska J.

1 Nachman R. J.

1 Olczak J.

1 Olejnik J.

1 Ołdziej S.

1 University P.

Search results

Chromium(III) complexes with DL-methionine and L-cysteine

Chelating ability of proctolin tetrazole analogue

Effect of tetrazole moiety on coordinating efficiency of deltorphin.