EPR study of Cu(II) in N-terminal lobe fragment of hen ovotransferrin

The N-terminal lobe fragment of hen ovotransferrin was prepared by trypsin digestion and the following gel filtration and ion-exchange chromatography. EPR spectra of Cu(II) complex of the N-terminal fragment were recorded independently from the C-terminal lobe and a major spectrum of the copper(II) complex showed g_∥ = 2.300 and g_⊥ = 2.061 with A^Cu_∥ = 14.0 mT, A^Cu_⊥ = 2.20 mT, which had a superhyperfine splitting (A^N_⊥ = 1.44 mT) of a nitrogen ligand, which may correspond to type A-1 site of copper binding position in the N-terminal lobe of hen ovotransferrin.