Dichloromethane dehalogenase with improved catalytic activity isolated from a fast-growing dichloromethane-utilizing bacterium
| Autor: | Christine Egli, Rudolf Scholtz, Thomas Leisinger, Alasdair M. Cook, Lawrence P. Wackett |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 1988 |
| Předmět: |
Immunodiffusion
Lyases Enzyme-Linked Immunosorbent Assay Microbiology Substrate Specificity chemistry.chemical_compound Dichloromethane dehalogenase ddc:570 Hydrocarbons Chlorinated Amino Acid Sequence Amino Acids Molecular Biology Dehalogenase chemistry.chemical_classification Methylene Chloride Bacteria biology Immune Sera Nucleic Acid Hybridization Glutathione Enzyme assay Amino acid Kinetics Enzyme Genes chemistry Biochemistry Genes Bacterial biology.protein Energy source Glutathione binding Research Article |
| Popis: | A methylotrophic bacterium, denoted strain DM11, was isolated from groundwater and shown to utilize dichloromethane or dibromomethane as the sole carbon and energy source. The new isolate grew at the high rate of 0.22 h-1 compared with 11 previously characterized dichloromethane-utilizing bacteria (micromax, 0.08 h-1). The dichloromethane dehalogenase from strain DM11 (group B enzyme) was purified by anion-exchange chromatography. It was shown to be substantially different from the set of dichloromethane dehalogenases from the 11 slow-growing strains (group A enzymes) that had previously been demonstrated to be identical. The Vmax for the group B enzyme was 97 mkat/kg of protein, some 5.6-fold higher than that of the group A enzymes. The group A dehalogenases showed hyperbolic saturation with the cosubstrate glutathione, whereas the group B enzyme showed positive cooperativity in glutathione binding. Only 1 of 15 amino acids occupied common positions at the N termini, and amino acid contents were substantially different in group A and group B dehalogenases. Immunological assays demonstrated weak cross-reactivity between the two enzymes. Despite the observed structural and kinetic differences, there is potentially evolutionary relatedness between group A and group B enzymes, as indicated by (i) hybridization of DM11 DNA with a gene probe of the group A enzyme, (ii) a common requirement for glutathione in catalysis, and (iii) similar subunit molecular weights of about 34,000. |
| Databáze: | OpenAIRE |
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