Rhus succedanea peroxidase and its compounds I and II

Abstract

In order to explore the process in which lacquer latex is oxidized and polymerized, peroxidase (RSP) was purified from Taiwanese lacquer ( Rhus succedanea) latex and characterized. The absorption and magnetic circular dichroism (MCD) spectra of ferric and ferrous peroxidase are quite similar to those of Chinese lacquer ( Rhus vernicifera) peroxidase (RVP), while spectral features of laccase contained in Taiwanese and Chinese lacquer are considerably different. Exogenous small ligands such as NO, CN −, and CO gave the MCD spectra characteristic to low-spin heme, indicating that these molecules can occupy an axial position. In addition, the electron spin resonance (ESR) spectra of NO-ferrous enzyme provided strong support for an imidazole group as the proximal (fifth) ligand. The treatment of native enzyme with H 2O 2 gave rise to compound I with a half-life of 10 min. Compound I was relatively stable (τ 1 2 = 10 min) but changed to compound II, giving the isosbestic points at 394 and 580 nm. This compound II returned to the resting state with a half-life of 165 min, giving the isosbestic point at 413 nm. The MCD spectra of compounds I and II were similar to those reported for horseradish peroxidase (HRP).