A team of researchers at the University of California has found that the histone H3-H4 tetramer is a copper reductase enzyme. In their paper published in the journal Science, the group describes two experiments they carried out that showed that histones are involved in reducing copper inside of cells. Johannes Rudolph and Karolin Luger with the University of Colorado at Boulder have published a Perspective piece in the same journal issue giving an outline of research involving histones and describing the work done by the team in California.