University of San Francisco 1 article published in JoVE Biochemistry Quantifying the Binding Interactions Between Cu(II) and Peptide Residues in the Presence and Absence of Chromophores Sohee Choi1, Jessica A. San Juan2, Marie C. Heffern2, Michael J. Stevenson1 1Department of Chemistry, University of San Francisco, 2Department of Chemistry, University of California, Davis This article focuses on the use of electronic absorption spectroscopy and isothermal titration calorimetry to probe and quantify the thermodynamics of Cu(II) binding to peptides and proteins.