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Proteolysis of Micellar β-Casein by Trypsin: Secondary Structure Characterization and Kinetic Modeling at Different Enzyme Concentrations

Tryptic proteolysis of protein micelles was studied using β-casein (β-CN) as an example. Hydrolysis of specific peptide bonds in β-CN leads to the degradation and rearrangement of the original micelles and the formation of new nanoparticles from their fragments. Samples of these nanoparticles dried...

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Autores principales: Vorob’ev, Mikhail M., Açıkgöz, Burçin Dersu, Güler, Günnur, Golovanov, Andrey V., Sinitsyna, Olga V.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9960058/
https://www.ncbi.nlm.nih.gov/pubmed/36835285
http://dx.doi.org/10.3390/ijms24043874
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author Vorob’ev, Mikhail M.
Açıkgöz, Burçin Dersu
Güler, Günnur
Golovanov, Andrey V.
Sinitsyna, Olga V.
author_facet Vorob’ev, Mikhail M.
Açıkgöz, Burçin Dersu
Güler, Günnur
Golovanov, Andrey V.
Sinitsyna, Olga V.
author_sort Vorob’ev, Mikhail M.
collection PubMed
description Tryptic proteolysis of protein micelles was studied using β-casein (β-CN) as an example. Hydrolysis of specific peptide bonds in β-CN leads to the degradation and rearrangement of the original micelles and the formation of new nanoparticles from their fragments. Samples of these nanoparticles dried on a mica surface were characterized by atomic force microscopy (AFM) when the proteolytic reaction had been stopped by tryptic inhibitor or by heating. The changes in the content of β-sheets, α-helices, and hydrolysis products during proteolysis were estimated by using Fourier-transform infrared (FTIR) spectroscopy. In the current study, a simple kinetic model with three successive stages is proposed to predict the rearrangement of nanoparticles and the formation of proteolysis products, as well as changes in the secondary structure during proteolysis at various enzyme concentrations. The model determines for which steps the rate constants are proportional to the enzyme concentration, and in which intermediate nano-components the protein secondary structure is retained and in which it is reduced. The model predictions were in agreement with the FTIR results for tryptic hydrolysis of β-CN at different concentrations of the enzyme.
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spelling pubmed-99600582023-02-26 Proteolysis of Micellar β-Casein by Trypsin: Secondary Structure Characterization and Kinetic Modeling at Different Enzyme Concentrations Vorob’ev, Mikhail M. Açıkgöz, Burçin Dersu Güler, Günnur Golovanov, Andrey V. Sinitsyna, Olga V. Int J Mol Sci Article Tryptic proteolysis of protein micelles was studied using β-casein (β-CN) as an example. Hydrolysis of specific peptide bonds in β-CN leads to the degradation and rearrangement of the original micelles and the formation of new nanoparticles from their fragments. Samples of these nanoparticles dried on a mica surface were characterized by atomic force microscopy (AFM) when the proteolytic reaction had been stopped by tryptic inhibitor or by heating. The changes in the content of β-sheets, α-helices, and hydrolysis products during proteolysis were estimated by using Fourier-transform infrared (FTIR) spectroscopy. In the current study, a simple kinetic model with three successive stages is proposed to predict the rearrangement of nanoparticles and the formation of proteolysis products, as well as changes in the secondary structure during proteolysis at various enzyme concentrations. The model determines for which steps the rate constants are proportional to the enzyme concentration, and in which intermediate nano-components the protein secondary structure is retained and in which it is reduced. The model predictions were in agreement with the FTIR results for tryptic hydrolysis of β-CN at different concentrations of the enzyme. MDPI 2023-02-15 /pmc/articles/PMC9960058/ /pubmed/36835285 http://dx.doi.org/10.3390/ijms24043874 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Vorob’ev, Mikhail M.
Açıkgöz, Burçin Dersu
Güler, Günnur
Golovanov, Andrey V.
Sinitsyna, Olga V.
Proteolysis of Micellar β-Casein by Trypsin: Secondary Structure Characterization and Kinetic Modeling at Different Enzyme Concentrations
title Proteolysis of Micellar β-Casein by Trypsin: Secondary Structure Characterization and Kinetic Modeling at Different Enzyme Concentrations
title_full Proteolysis of Micellar β-Casein by Trypsin: Secondary Structure Characterization and Kinetic Modeling at Different Enzyme Concentrations
title_fullStr Proteolysis of Micellar β-Casein by Trypsin: Secondary Structure Characterization and Kinetic Modeling at Different Enzyme Concentrations
title_full_unstemmed Proteolysis of Micellar β-Casein by Trypsin: Secondary Structure Characterization and Kinetic Modeling at Different Enzyme Concentrations
title_short Proteolysis of Micellar β-Casein by Trypsin: Secondary Structure Characterization and Kinetic Modeling at Different Enzyme Concentrations
title_sort proteolysis of micellar β-casein by trypsin: secondary structure characterization and kinetic modeling at different enzyme concentrations
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9960058/
https://www.ncbi.nlm.nih.gov/pubmed/36835285
http://dx.doi.org/10.3390/ijms24043874
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