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Protein Binding Characteristics of the Principal Green Tea Catechins: A QCM Study Comparing Crude Extract to Pure EGCG

Label-free detection methods such as the quartz crystal microbalance (QCM) are well suited to the analysis of molecular interactions in complex mixtures such as crude botanical extracts. In the present study, the binding characteristics of epigallocatechin gallate (EGCG) and crude green tea extract...

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Autores principales: Ali, Elsadig E., Elmakki, Mohamed O., Gavette, Miranda L., Doyle, Brian J., Timpe, Shannon J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Hindawi 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6881586/
https://www.ncbi.nlm.nih.gov/pubmed/31827928
http://dx.doi.org/10.1155/2019/6154170
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author Ali, Elsadig E.
Elmakki, Mohamed O.
Gavette, Miranda L.
Doyle, Brian J.
Timpe, Shannon J.
author_facet Ali, Elsadig E.
Elmakki, Mohamed O.
Gavette, Miranda L.
Doyle, Brian J.
Timpe, Shannon J.
author_sort Ali, Elsadig E.
collection PubMed
description Label-free detection methods such as the quartz crystal microbalance (QCM) are well suited to the analysis of molecular interactions in complex mixtures such as crude botanical extracts. In the present study, the binding characteristics of epigallocatechin gallate (EGCG) and crude green tea extract solutions to bovine serum albumin (BSA) have been investigated. The adsorbed mass levels onto BSA-functionalized surfaces were measured at various solution concentrations. Langmuir and Freundlich isotherms were used to model the adsorption data. The Langmuir isotherm better described the adsorption behavior with correlations of 0.68 and 0.70 for the EGCG and the crude extract solutions, respectively. The better fit of the Langmuir model indicates that adsorption occurs homogeneously and that aggregation is negligible. The mass saturation is estimated to be 58% higher for the crude green tea solution as compared to the pure EGCG solution (7.9 ng/cm(2) for green tea and 5 ng/cm(2) for EGCG). The increased adsorption for the crude extract indicates that the additional tea chemical constituents are binding to alternate sites on the protein molecule and that competitive binding is a nondominant effect. However, a reduced adsorption rate for the crude extract was also observed, indicating some presence of competitive mechanisms. The results demonstrate the utility of the QCM for the analysis of protein binding in crude mixtures as well as pure compounds.
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spelling pubmed-68815862019-12-11 Protein Binding Characteristics of the Principal Green Tea Catechins: A QCM Study Comparing Crude Extract to Pure EGCG Ali, Elsadig E. Elmakki, Mohamed O. Gavette, Miranda L. Doyle, Brian J. Timpe, Shannon J. Biochem Res Int Research Article Label-free detection methods such as the quartz crystal microbalance (QCM) are well suited to the analysis of molecular interactions in complex mixtures such as crude botanical extracts. In the present study, the binding characteristics of epigallocatechin gallate (EGCG) and crude green tea extract solutions to bovine serum albumin (BSA) have been investigated. The adsorbed mass levels onto BSA-functionalized surfaces were measured at various solution concentrations. Langmuir and Freundlich isotherms were used to model the adsorption data. The Langmuir isotherm better described the adsorption behavior with correlations of 0.68 and 0.70 for the EGCG and the crude extract solutions, respectively. The better fit of the Langmuir model indicates that adsorption occurs homogeneously and that aggregation is negligible. The mass saturation is estimated to be 58% higher for the crude green tea solution as compared to the pure EGCG solution (7.9 ng/cm(2) for green tea and 5 ng/cm(2) for EGCG). The increased adsorption for the crude extract indicates that the additional tea chemical constituents are binding to alternate sites on the protein molecule and that competitive binding is a nondominant effect. However, a reduced adsorption rate for the crude extract was also observed, indicating some presence of competitive mechanisms. The results demonstrate the utility of the QCM for the analysis of protein binding in crude mixtures as well as pure compounds. Hindawi 2019-10-30 /pmc/articles/PMC6881586/ /pubmed/31827928 http://dx.doi.org/10.1155/2019/6154170 Text en Copyright © 2019 Elsadig E. Ali et al. http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Ali, Elsadig E.
Elmakki, Mohamed O.
Gavette, Miranda L.
Doyle, Brian J.
Timpe, Shannon J.
Protein Binding Characteristics of the Principal Green Tea Catechins: A QCM Study Comparing Crude Extract to Pure EGCG
title Protein Binding Characteristics of the Principal Green Tea Catechins: A QCM Study Comparing Crude Extract to Pure EGCG
title_full Protein Binding Characteristics of the Principal Green Tea Catechins: A QCM Study Comparing Crude Extract to Pure EGCG
title_fullStr Protein Binding Characteristics of the Principal Green Tea Catechins: A QCM Study Comparing Crude Extract to Pure EGCG
title_full_unstemmed Protein Binding Characteristics of the Principal Green Tea Catechins: A QCM Study Comparing Crude Extract to Pure EGCG
title_short Protein Binding Characteristics of the Principal Green Tea Catechins: A QCM Study Comparing Crude Extract to Pure EGCG
title_sort protein binding characteristics of the principal green tea catechins: a qcm study comparing crude extract to pure egcg
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6881586/
https://www.ncbi.nlm.nih.gov/pubmed/31827928
http://dx.doi.org/10.1155/2019/6154170
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