Peroxidase-catalyzed-3-(glutathion-S-yl)-p,p'-biphenol formation

Oxidation of p,p'-biphenol with horseradish peroxidase (HRP)-hydrogen peroxide in the presence of bovine serum albumin or with bone marrow cell homogenate-hydrogen peroxide resulted in the formation of reactive products that conjugate with protein. Glutathione prevented the protein binding. Glutathione readily reacted with p,p'-biphenoquinone, the principal oxidation product of p,p'-biphenol in the HRP-hydrogen peroxide system and resulted in the formation of several glutathione conjugates, p,p'-biphenol and small amounts of oxidized glutathione. The major glutathione conjugate was identified as 3-(glutathion-S-yl)-p,p'-biphenol by high field nuclear magnetic resonance and fast atom bombardment mass spectrometry. The same conjugate was formed in the bone marrow homogenate-hydrogen peroxide system. p,p'-Biphenoquinone reduction by glutathione to p,p'-biphenol without glutathione oxidation was explained by the rapid reduction of p,p'-biphenoquinone by 3-(glutathion-S-yl)-p,p'-biphenol.