title: Purification and characterization of an intracellular peroxidase from Streptomyces cyaneus.
abstract: An intracellular peroxidase (EC 1.11.1.7) from Streptomyces cyaneus was purified to homogeneity. The enzyme had a molecular weight of 185,000 and was composed of two subunits of equal size. It had an isoelectric point of 6.1. The enzyme had a peroxidase activity toward o-dianisidine with a Km of 17.8 microM and a pH optimum of 5.0. It also showed catalase activity with a Km of 2.07 mM H2O2 and a pH optimum of 8.0. The purified enzyme did not catalyze C alpha-C beta bond cleavage of 1,3-dihydroxy-2-(2-methoxyphenoxy)-1-(4-ethoxy-3-methoxyphenyl) propane, a nonphenolic dimeric lignin model compound. The spectrum of the peroxidase showed a soret band at 405 nm, which disappeared after reduction with sodium dithionite, indicating that the enzyme is a hemoprotein. Testing the effects of various inhibitors on the enzyme activity showed that it is a bifunctional enzyme having catalase and peroxidase activities.
authors.affiliation: Institute of Biotechnology, ETH-Zürich, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Mliki
authors.forename: W
authors.initials: W
authors.lastname: Zimmermann
mesh_terms: D001673:Biodegradation, Environmental; D002852:Chromatography, Ion Exchange; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008031:Lignin / Q000378:metabolism*; D009195:Peroxidase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D013302:Streptomyces / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: D008031:Lignin; D009195:Peroxidase