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Imidazole-rich copper peptides as catalysts in xenobiotic degradation


Begum, Sharifa Zaithun and Mohd Nizam, Nurul Shairah and Muhamad, Azira and Saiman, Mohd Izham and Crouse, Karen Anne and Abdul Rahman, Mohd Basyaruddin (2020) Imidazole-rich copper peptides as catalysts in xenobiotic degradation. PLoS One, 15 (11). pp. 1-15. ISSN 1932-6203


Laccases, oxidative copper-enzymes found in fungi and bacteria were used as the basis in the design of nona- and tetrapeptides. Laccases are known to be excellent catalysts for the degradation of phenolic xenobiotic waste. However, since solvent extraction of laccases is environmentally-unfriendly and yields obtained are low, they are less preferred compared to synthetic catalysts. The histidine rich peptides were designed based on the active site of laccase extracted from Trametes versicolor through RCSB Protein Data Bank, LOMETS and PyMol software. The peptides were synthesized using Fmoc-solid phase peptide synthesis (SPPS) with 30–40% yield. These peptides were purified and characterized using LC-MS (purities >75%), FTIR and NMR spectroscopy. Synthesized copper(II)-peptides were crystallized and then analyzed spectroscopically. Their structures were elucidated using 1D and 2D NMR. Standards (o,m,p-cresol, 2,4-dichlorophenol) catalysed using laccase from Trametes versicolor (0.66 U/mg) were screened under different temperatures and stirring rate conditions. After optimizing the degradation of the standards with the best reaction conditions reported herein, medications with phenolic and aromatic structures such as ibuprofen, paracetamol (acetaminophen), salbutamol, erythromycin and insulin were screened using laccase (positive control), apo-peptides and copper-peptides. Their activities evaluated using GC-MS, were compared with those of peptide and copper-peptide catalysts. The tetrapeptide was found to have the higher degradation activity towards salbutamol (96.8%) compared with laccase at 42.8%. Ibuprofen (35.1%), salbutamol (52.9%) and erythromycin (49.7%) were reported to have the highest degradation activities using Cu-tetrapeptide as catalyst when compared with the other medications. Consequently, o-cresol (84%) was oxidized by Tp-Cu while the apo-peptides failed to oxidize the cresols. Copper(II)-peptides were observed to have higher catalytic activity compared to their parent peptides and the enzyme laccase for xenobiotic degradation.

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Additional Metadata

Item Type: Article
Divisions: Faculty of Science
DOI Number: https://doi.org/10.1371/journal.pone.0238147
Publisher: Public Library of Science
Keywords: Laccases; FTIR; Xenobiotic; Peptide
Depositing User: Ms. Nuraida Ibrahim
Date Deposited: 03 Sep 2021 09:08
Last Modified: 03 Sep 2021 09:08
Altmetrics: http://www.altmetric.com/details.php?domain=psasir.upm.edu.my&doi=10.1371/journal.pone.0238147
URI: http://psasir.upm.edu.my/id/eprint/89268
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