Copper-peptides mimicking catalytic activity of laccase in oxidation reactions

Laccase, an oxidative enzyme naturally found in fungi and bacteria, has been widely used in the fields of chemical and bio-catalysis. Its active site contains several copper ions making it very interesting for studies related to the structure and catalytic mechanisms. However, extracting laccase...

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Main Author:	Begum, Sharifa Zaithun
Format:	Thesis
Language:	English
Published:	2020
Subjects:	Laccase Peptides - Synthesis Oxidation-reduction reaction
Online Access:	http://psasir.upm.edu.my/id/eprint/90718/1/FS%202020%2029%20IR.pdf
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spelling	my-upm-ir.907182021-09-08T00:35:31Z Copper-peptides mimicking catalytic activity of laccase in oxidation reactions 2020-07 Begum, Sharifa Zaithun Laccase, an oxidative enzyme naturally found in fungi and bacteria, has been widely used in the fields of chemical and bio-catalysis. Its active site contains several copper ions making it very interesting for studies related to the structure and catalytic mechanisms. However, extracting laccase uses large amounts of organic solvents to attain low yield; making it a less preferred choice for all green chemistry applications. The significance of this study is to mimic and enhance the catalytic activity of the highest oxidation activity reported laccase from Trametes versicolor. The four peptide sequences of the active sites found in most laccases was designed into nona (Np), hepta (Hp), tetrapeptides (Tp1 and Tp2) using computational techniques. The peptides were synthesized using Fmoc SPPS, analyzed and purified using HPLC and LC-MS. Copper(II)-peptides identified as Np-CuC, Np-CuS, Np-CuN, Hp-CuC, Hp-CuS, Hp- CuN, Tp1-CuC, Tp1-CuS, Tp2-CuC and Tp2-CuS were synthesized, crystallized and analyzed using FTIR, Raman, NMR, AAS, XPS and CD. Different molar ratio of peptides to copper(II) ions were analyzed for binding studies. These peptides and copper-peptides were tested for their catalytic activity in oxidation reaction of benzyl alcohol where both oxidation to benzaldehyde and disproportionation to toluene and phenol were achieved simulataneously. Np-CuC was observed to have higher catalytic activity (62.3%, 100% selectivity) than laccase (40.8%, 19.1% selectivity) towards benzaldehyde. They were also used as catalysts in the degradation of twelve pharmaceutical active compounds (PhACs). Tp2-CuS (1:2) proved to be a better catalyst in the degradation of PhACs. Oxidation of 5-ASA and DCA catalyzed by these copper peptides where Hp-CuS provided the highest yield of the oxidized product (46.5%). These activities were compared with laccase (positive control) and no catalyst (negative control). Overall, Np-CuC, Tp2-CuS and Hp-CuS were found to be better catalysts for oxidation reactions compared to their parent peptides and laccase. Laccase Peptides - Synthesis Oxidation-reduction reaction 2020-07 Thesis http://psasir.upm.edu.my/id/eprint/90718/ http://psasir.upm.edu.my/id/eprint/90718/1/FS%202020%2029%20IR.pdf text en public doctoral Universiti Putra Malaysia Laccase Peptides - Synthesis Oxidation-reduction reaction Abdul Rahman, Mohd Basyaruddin
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English
advisor	Abdul Rahman, Mohd Basyaruddin
topic	Laccase Peptides - Synthesis Oxidation-reduction reaction
spellingShingle	Laccase Peptides - Synthesis Oxidation-reduction reaction Begum, Sharifa Zaithun Copper-peptides mimicking catalytic activity of laccase in oxidation reactions
description	Laccase, an oxidative enzyme naturally found in fungi and bacteria, has been widely used in the fields of chemical and bio-catalysis. Its active site contains several copper ions making it very interesting for studies related to the structure and catalytic mechanisms. However, extracting laccase uses large amounts of organic solvents to attain low yield; making it a less preferred choice for all green chemistry applications. The significance of this study is to mimic and enhance the catalytic activity of the highest oxidation activity reported laccase from Trametes versicolor. The four peptide sequences of the active sites found in most laccases was designed into nona (Np), hepta (Hp), tetrapeptides (Tp1 and Tp2) using computational techniques. The peptides were synthesized using Fmoc SPPS, analyzed and purified using HPLC and LC-MS. Copper(II)-peptides identified as Np-CuC, Np-CuS, Np-CuN, Hp-CuC, Hp-CuS, Hp- CuN, Tp1-CuC, Tp1-CuS, Tp2-CuC and Tp2-CuS were synthesized, crystallized and analyzed using FTIR, Raman, NMR, AAS, XPS and CD. Different molar ratio of peptides to copper(II) ions were analyzed for binding studies. These peptides and copper-peptides were tested for their catalytic activity in oxidation reaction of benzyl alcohol where both oxidation to benzaldehyde and disproportionation to toluene and phenol were achieved simulataneously. Np-CuC was observed to have higher catalytic activity (62.3%, 100% selectivity) than laccase (40.8%, 19.1% selectivity) towards benzaldehyde. They were also used as catalysts in the degradation of twelve pharmaceutical active compounds (PhACs). Tp2-CuS (1:2) proved to be a better catalyst in the degradation of PhACs. Oxidation of 5-ASA and DCA catalyzed by these copper peptides where Hp-CuS provided the highest yield of the oxidized product (46.5%). These activities were compared with laccase (positive control) and no catalyst (negative control). Overall, Np-CuC, Tp2-CuS and Hp-CuS were found to be better catalysts for oxidation reactions compared to their parent peptides and laccase.
format	Thesis
qualification_level	Doctorate
author	Begum, Sharifa Zaithun
author_facet	Begum, Sharifa Zaithun
author_sort	Begum, Sharifa Zaithun
title	Copper-peptides mimicking catalytic activity of laccase in oxidation reactions
title_short	Copper-peptides mimicking catalytic activity of laccase in oxidation reactions
title_full	Copper-peptides mimicking catalytic activity of laccase in oxidation reactions
title_fullStr	Copper-peptides mimicking catalytic activity of laccase in oxidation reactions
title_full_unstemmed	Copper-peptides mimicking catalytic activity of laccase in oxidation reactions
title_sort	copper-peptides mimicking catalytic activity of laccase in oxidation reactions
granting_institution	Universiti Putra Malaysia
publishDate	2020
url	http://psasir.upm.edu.my/id/eprint/90718/1/FS%202020%2029%20IR.pdf
_version_	1747813650527158272

Copper-peptides mimicking catalytic activity of laccase in oxidation reactions

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