Role of tetrachloro-1,4-benzoquinone reductase in phenylalanine hydroxylation system and pentachlorophenol degradation in Bacillus cereus AOA-CPS1
| Autor: | Ajit Kumar, Ademola O. Olaniran, Oladipupo A. Aregbesola, Mduduzi P. Mokoena |
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| Rok vydání: | 2020 |
| Předmět: |
Pentachlorophenol
genetic structures Chloranil Phenylalanine 02 engineering and technology Reductase Hydroxylation Biochemistry 03 medical and health sciences chemistry.chemical_compound Bacillus cereus Bacterial Proteins Structural Biology Enzyme kinetics Molecular Biology 030304 developmental biology chemistry.chemical_classification 0303 health sciences Chemistry General Medicine 021001 nanoscience & nanotechnology Galactosyltransferases Kinetics Enzyme Dehydratase Sodium azide Specific activity 0210 nano-technology Oxidoreductases |
| Zdroj: | International journal of biological macromolecules. 161 |
| ISSN: | 1879-0003 |
| Popis: | This study reports a ≅12.5 kDa protein tetrachloro-1,4-benzoquinone reductase (CpsD) from Bacillus cereus strain AOA-CPS1 (BcAOA). CpsD is purified to homogeneity with a total yield of 35% and specific activity of 160 U·mg−1 of protein. CpsD showed optimal activity at pH 7.5 and 40 °C. The enzyme was found to be functionally stable between pH 7.0–7.5 and temperature between 30 °C and 35 °C. CpsD activity was enhanced by Fe2+ and inhibited by sodium azide and SDS. CpsD followed Michaelis-Menten kinetic exhibiting an apparent vmax, Km, kcat and kcat/Km values of 0.071 μmol·s−1, 94 μmol, 0.029 s−1 and 3.13 × 10−4 s−1·μmol−1, respectively, for substrate tetrachloro-1,4-benzoquinone. The bioinformatics analysis indicated that CpsD belongs to the PCD/DCoH superfamily, with specific conserved protein domains of pterin-4α-carbinolamine dehydratase (PCD). This study proposed that CpsD catalysed the reduction of tetrachloro-1,4-benzoquinone to tetrachloro-p-hydroquinone and released the products found in phenylalanine hydroxylation system (PheOHS) via a Ping-Pong or atypical ternary mechanism; and regulate expression of phenylalanine 4-monooxygenase by blocking reverse flux in BcAOA PheOHS using a probable Yin-Yang mechanism. The study also concluded that CpsD may play a catalytic and regulatory role in BcAOA PheOHS and pentachlorophenol degradation pathway. |
| Databáze: | OpenAIRE |
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