Copper(II) complexes of the histidine-containing tripeptides glyclyl-L-histidylglycine (GlyHisGly), glycylglycyl-L-histidine (GlyGlyHis), and L-pyroglutamyl-L-histidyl-L-prolinamide (trf), and the dipeptide L-pyroglutamyl-L-histidine methyl ester (pghme), have been studied by pH-metric and spectrophotometric methods. It was found that, similarly as for glycyl-L-histidine (GlyHis), GlyHisGly forms a complex [CuAH-1], but bis complexes are also formed in low concentration. For GlyGlyHis, only the highly stable species [CuAH-2]- is formed. A complex [CuAH-2]- is also formed with trf and pghme which indicates that the prolinamide side-chain in trf does not take part in the co-ordination. The sequence of deprotonation of the N1H group of the imidazole side-chain is as follows: GlyHisGly > GlyHis > pghme > trf > GlyGlyHis.
|Number of pages||4|
|Journal||Journal of the Chemical Society, Dalton Transactions|
|Publication status||Published - Dec 1 1984|
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