A fluorimetric guaiacol method for thyroid peroxidase activity

Abstract

A sensitive fluorimetric method with guaiacol as the hydrogen donor for peroxidase activity is described. The gist of this method is measurement of the fluorescence (excitation, 300 nm; emission, 340 nm) in cyclohexane of mainly a guaiacol dimer which forms in the early phase of the color formation. Optimum conditions of the reaction were compared for horseradish peroxidase and rat thyroid peroxidase preparations. The fluorescence intensity obtained by this method using an enzyme preparation from 1 20 of a rat thyroid gland correlated well with the color development by the guaiacol method using the same preparation from whole glands of a rat. © 1982.