ABSTRACT
BCPs consist of a single polypeptide chain of 90-150 residues that bind a single type 1 copper center (Fig. 2 ). Some BCPs transfer electrons between contiguous donor and acceptor molecules, whereas others ferry electrons over long distances. BCPs are present in the three kingdoms of life. This suggests the existence of an ancestor prior to the divergence of archea, bacteria and eukarya, i.e., at least 1.5 billion years previous to the beginning of aerobic life [2 1 ]. Instead, blue oxidases are found only in higher eukaryotes.
