Guaiacol (2-Methoxyphenol)

Guaiacol is a phenolic natural product first isolated from Guaiac resin and the oxidation of lignin. Guaiacol is readily oxidized by the heme iron of peroxidases including the peroxidase of cyclooxygenase (COX) enzymes. It therefore serves as a reducing co-substrate for COX reactions.¹ The color yield per peroxide at 470 nm is 6,650 (M peroxide reduced)-1 cm-1.^2,3,4 Two moles of guaiacol are oxidized for each mole of hydroperoxide reduced by the peroxidase. The resulting guaiacol chromophore can be used for the colorimetric determination of hydroperoxidase activity.

1.Markey, C.M., Alward, A., Weller, P.E., et al.Quantitative studies of hydroperoxide reduction by prostaglandin H synthase. Reducing substrate specificity and the relationship of peroxidase to cyclooxygenase activitiesJ. Biol. Chem.2626266-6279(1987) 2.Doerge, D.R., Divi, R.L., and Churchwell, M.I.Identification of the colored guaiacol oxidation product produced by peroxidasesAnal. Biochem.25010-17(1997) 3.Kulmacz, R.J., and Lands, W.E.M.Quantitative similarities in the several actions of cyanide on prostaglandin H synthaseProstaglandins29175-190(1985) 4.Marquez, L.A., and Dunford, H.B.Mechanism of the oxidation of 3,5,3',5'-tetramethylbenzidine by myeloperxidase determined by transient-and steady-state kineticsBiochemistry369349-9355(1997)