Cyclic voltammetry and differential pulse stripping voltammetry were used to investigate the electrochemistry of human saliva and proteins of glycoprotein, mucin, lacto-peroxidase, alkaline and acid phosphatase, amylase, and lysozyme. Effects from buffer type, concentration, deposition time, scanning rate, cycling, and starting potential were included in selected tests. Deionized water buffer unequivocally revealed characteristic effects from only protein. Upon reduction, all proteins displayed either one or two peaks in the -0.36 to -0.51 V vs Ag/AgCI range, while upon oxidation all proteins displayed a peak in the -0.38 to -0.33 V range. In phosphate or Tris buffers, reduction peak potentials decreased to around -0.60 V, in agreement to literature values for proteins containing disulfide bonds. Selected proteins also displayed redox behavior around -1.0 V, which was attributable to the O2/H2O2 couple. Processes from both dissolved reactants and adsorbed species were used to explain various effects.
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