title: Purification and characterization of 6-chlorohydroxyquinol 1,2-dioxygenase from Streptomyces rochei 303: comparison with an analogous enzyme from Azotobacter sp. strain GP1.
abstract: The enzyme which cleaves the benzene ring of 6-chlorohydroxyquinol was purified to apparent homogeneity from an extract of 2,4,6-trichlorophenol-grown cells of Streptomyces rochei 303. Like the analogous enzyme from Azotobacter sp. strain GP1, it exhibited a highly restricted substrate specificity and was able to cleave only 6-chlorohydroxyquinol and hydroxyquinol and not catechol, chlorinated catechols, or pyrogallol. No extradiol-cleaving activity was observed. In contrast to 6-chlorohydroxyquinol 1,2-dioxygenase from Azotobacter sp. strain GP1, the S. rochei enzyme had a distinct preference for 6-chlorohydroxyquinol over hydroxyquinol (kcat/Km = 1.2 and 0.57 s-1.microM-1, respectively). The enzyme from S. rochei appears to be a dimer of two identical 31-kDa subunits. It is a colored protein and was found to contain 1 mol of iron per mol of enzyme. The NH2-terminal amino acid sequences of 6-chlorohydroxyquinol 1,2-dioxygenase from S. rochei 303 and from Azotobacter sp. strain GP1 showed a high degree of similarity.
authors.affiliation: Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino.
authors.forename: O
authors.initials: O
authors.lastname: Zaborina
authors.forename: M
authors.initials: M
authors.lastname: Latus
authors.forename: J
authors.initials: J
authors.lastname: Eberspächer
authors.forename: L A
authors.initials: LA
authors.lastname: Golovleva
authors.forename: F
authors.initials: F
authors.lastname: Lingens
mesh_terms: D000595:Amino Acid Sequence; D001395:Azotobacter / Q000201:enzymology; D001673:Biodegradation, Environmental; D002733:Chlorophenols / Q000378:metabolism; D049308:Dioxygenases; D006873:Hydroquinones / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D007501:Iron / Q000032:analysis; D008298:Maleates / Q000378:metabolism; D008667:Metalloproteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D008969:Molecular Sequence Data; D010105:Oxygenases / Q000378:metabolism*; D011487:Protein Conformation; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D013302:Streptomyces / Q000201:enzymology*; D013379:Substrate Specificity
chemical_list: C091167:6-chlorohydroxyquinol; D002733:Chlorophenols; D006873:Hydroquinones; D008298:Maleates; D008667:Metalloproteins; C013038:hydroxyhydroquinone; C011905:maleoylacetic acid; C079154:2-chloromaleylacetate; D007501:Iron; D010105:Oxygenases; C091168:6-chlorohydroxyquinol 1,2-dioxygenase; D049308:Dioxygenases