Peroxidase from leaves of royal palm tree Roystonea regia: purification and some properties

Screening of tropical plants demonstrated high peroxidase activity in leave s of some species of palms. Using the leaves of royal palm Roystonea regia as a soul-cc, the peroxidase has been isolated to homogeneity. The enzyme p urification steps included homogenization, (NH4)(2)SO4 precipitation, extra ction of palm leaf colored compounds and consecutive chromatography on Phen yl-Sepharose, Sephacryl S100 and DEAE-Toyopearl. The novel peroxidase was c haracterized as having a specific activity of 6170 U/mg, RZ 3.0, molecular weight of 51 kDa and isoelectric point pI 3.5. The electronic spectrum of R PP is characteristic for plant peroxidases with a Soret maximum at 403 nm a nd maxima in a visible region at 492 and 633 nm, respectively. The substrat e specificity of royal palm tree peroxidase (RPTP) is distinct from the spe cificity of other plant peroxidases. The best substrates for RPTP are ferul ic acid and 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid). The pal m peroxidase exhibits an unusually high thermostability inactivating at 90 degreesC with k(inac) of 1.5 x 10(-2) min(-1). (C) 2001 Elsevier Science Ir eland Ltd. All rights reserved.