Binding ability of Cu2+ ions by opiate-like fragments of bovine casein.
The coordination modes of Cu(II) to alpha-casein (90-95) and alpha-casein (90-96) peptides with opioid activity isolated from pepsin hydrolisates of alpha-casein were investigated by means of electron paramagnetic resonance, absorption, and circular dichroism spectroscopy and potentiometry. The results allow the identification of the complex species involved and the attribution of the spectral data set to the various complex structures. According to the spectroscopic data, a phenolate side-chain of Tyr residue belonging to the Gly-Tyr-Leu or Gly-Tyr-Leu-Gln fragment of the peptides is involved in the metal coordination in a complex which is a minor species at neutral pH range.
Chruścińska
E
E
Institute of General and Food Chemistry, Technical University of Lódź, Poland.
Dyba
M
M
Micera
G
G
Ambroziak
W
W
Olczak
J
J
Zabrocki
J
J
Kozłowski
H
H
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002364:Caseins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D003300:Copper / Q000378:metabolism*; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009294:Narcotics / Q000737:chemistry* / Q000378:metabolism*; D009842:Oligopeptides / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D010446:Peptide Fragments / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014443:Tyrosine / Q000737:chemistry
D002364:Caseins; D009294:Narcotics; D009842:Oligopeptides; D010446:Peptide Fragments; D014443:Tyrosine; D003300:Copper