Biochemical characterization of a thermostable cobalt- or copper-dependent polyphenol oxidase with dye decolorizing ability from Geobacillus sp. JS12
| Autor: | Han-Woo Kim, Soo-Jung Moon, Sung-Jong Jeon |
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| Rok vydání: | 2018 |
| Předmět: |
0301 basic medicine
Sequence Homology Bioengineering Multicopper oxidase Applied Microbiology and Biotechnology Biochemistry Polyphenol oxidase Substrate Specificity 03 medical and health sciences chemistry.chemical_compound Bacterial Proteins Amino Acid Sequence Cloning Molecular Catechol oxidase Coloring Agents Laccase chemistry.chemical_classification ABTS 030102 biochemistry & molecular biology biology Chemistry Temperature Substrate (chemistry) Geobacillus Polyphenols Cobalt Nile blue Trace Elements 030104 developmental biology Enzyme biology.protein Oxidation-Reduction Catechol Oxidase Copper Biotechnology Nuclear chemistry |
| Zdroj: | Enzyme and microbial technology. 118 |
| ISSN: | 1879-0909 |
| Popis: | A putative laccase-like gene, GPPO, encoding a protein of 17.2 kDa and belonging to the multicopper oxidase family, was cloned and overexpressed in Escherichia coli cells. The purified recombinant protein GPPO is homodecameric protein with a molecular weight of 171.6 kDa. GPPO was not detected the ultraviolet-visible spectroscopy (UV/Vis) spectrum of typical laccases. Co2+ or Cu2+ was essential for substrate oxidation of GPPO, and the enzyme contained 1 mol of Co or Cu per mole of protein. The optimum pH required for the oxidation of 2,2'-azino-bis(3-ethylbenzothazoline-6-sulfonate) (ABTS) and 2,6-dimethoxyphenol (DMP) was 4.5 and 5.5, respectively, and the optimum temperature was 75 °C. The half-life of heat inactivation was about 8 min at 80 °C and 90 min at 90 °C, in the presence of Cu2+ and Co2+, respectively. The catalytic efficiency (kcat/Km) of GPPO containing Co2+ was 68 times higher than that of GPPO containing Cu2+. The enzyme reaction was inhibited by conventional inhibitors of laccase like metal chelators and thiol compounds. GPPO incubated with Cu2+ or Co2+ for 48 h decolorizes 45% or 47% of Nile blue, respectively. This is the first report of a novel thermostable polyphenol oxidase that shows the cobalt-dependent laccase activity and dye decolorization ability. |
| Databáze: | OpenAIRE |
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