title: Spectral characterization and chemical modification of catalase-peroxidase from Streptomyces sp.
abstract: Catalase-peroxidase was purified to near homogeneity from Streptomyces sp. The enzyme was composed of two subunits with a molecular mass of 78 kDa and contained 1.05 mol of protoporphyrin IX/mol of dimeric protein. The absorption and resonance Raman spectra of the native and its cyano-enzyme were closely similar to those of other heme proteins with a histidine as the fifth ligand. However, the peak from tyrosine ring at approximately 1612 cm-1, which is unique in catalases, was not found in resonance Raman spectra of catalase-peroxidase. The electron paramagnetic resonance spectrum of the native enzyme revealed uniquely two sets of rhombic signals, which were converted to a single high spin, hexacoordinate species after the addition of sodium formate. Cyanide bound to the sixth coordination position of the heme iron, thereby converting the enzyme to a low spin, hexacoordinate species. The time-dependent inactivation of the enzyme with diethyl pyrocarbonate and its kinetic analysis strongly suggested the occurrence of histidine residue. From the above-mentioned spectroscopic results and chemical modification, it was deduced that the native enzyme is predominantly in the high spin, ferric form and has a histidine as the fifth ligand.
authors.affiliation: Department of Microbiology, College of Natural Sciences, Seoul National University, Republic of Korea.
authors.forename: H D
authors.initials: HD
authors.lastname: Youn
authors.forename: Y I
authors.initials: YI
authors.lastname: Yim
authors.forename: K
authors.initials: K
authors.lastname: Kim
authors.forename: Y C
authors.initials: YC
authors.lastname: Hah
authors.forename: S O
authors.initials: SO
authors.lastname: Kang
mesh_terms: D002374:Catalase / Q000737:chemistry* / Q000302:isolation & purification; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D004578:Electron Spin Resonance Spectroscopy; D008970:Molecular Weight; D010544:Peroxidases / Q000737:chemistry* / Q000302:isolation & purification; D013057:Spectrum Analysis; D013302:Streptomyces / Q000201:enzymology*; D013329:Structure-Activity Relationship
chemical_list: D010544:Peroxidases; D002374:Catalase; D004047:Diethyl Pyrocarbonate