Considerations about the Continuous Assay Methods, Spectrophotometric and Spectrofluorometric, of the Monophenolase Activity of Tyrosinase
With the purpose to obtain the more useful tyrosinase assay for the monophenolase activity of tyrosinase between the spectrofluorometric and spectrophotometric continuous assays, simulated assays were made by means of numerical integration of the equations that characterize the mechanism of monophen...
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2021-08-01
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Article |
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DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Pablo García-Molina José Luis Munoz-Munoz Joaquin A. Ortuño José Neptuno Rodríguez-López Pedro Antonio García-Ruiz Francisco García-Cánovas Francisco García-Molina |
spellingShingle |
Pablo García-Molina José Luis Munoz-Munoz Joaquin A. Ortuño José Neptuno Rodríguez-López Pedro Antonio García-Ruiz Francisco García-Cánovas Francisco García-Molina Considerations about the Continuous Assay Methods, Spectrophotometric and Spectrofluorometric, of the Monophenolase Activity of Tyrosinase Biomolecules tyrosinase polyphenol oxidase monophenolase activity fluorimetric method spectrophotometric method LOD<sup>M</sup> |
author_facet |
Pablo García-Molina José Luis Munoz-Munoz Joaquin A. Ortuño José Neptuno Rodríguez-López Pedro Antonio García-Ruiz Francisco García-Cánovas Francisco García-Molina |
author_sort |
Pablo García-Molina |
title |
Considerations about the Continuous Assay Methods, Spectrophotometric and Spectrofluorometric, of the Monophenolase Activity of Tyrosinase |
title_short |
Considerations about the Continuous Assay Methods, Spectrophotometric and Spectrofluorometric, of the Monophenolase Activity of Tyrosinase |
title_full |
Considerations about the Continuous Assay Methods, Spectrophotometric and Spectrofluorometric, of the Monophenolase Activity of Tyrosinase |
title_fullStr |
Considerations about the Continuous Assay Methods, Spectrophotometric and Spectrofluorometric, of the Monophenolase Activity of Tyrosinase |
title_full_unstemmed |
Considerations about the Continuous Assay Methods, Spectrophotometric and Spectrofluorometric, of the Monophenolase Activity of Tyrosinase |
title_sort |
considerations about the continuous assay methods, spectrophotometric and spectrofluorometric, of the monophenolase activity of tyrosinase |
publisher |
MDPI AG |
series |
Biomolecules |
issn |
2218-273X |
publishDate |
2021-08-01 |
description |
With the purpose to obtain the more useful tyrosinase assay for the monophenolase activity of tyrosinase between the spectrofluorometric and spectrophotometric continuous assays, simulated assays were made by means of numerical integration of the equations that characterize the mechanism of monophenolase activity. These assays showed that the rate of disappearance of monophenol (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi mathvariant="normal">V</mi><mrow><mi>ss</mi></mrow><mrow><mi mathvariant="normal">M</mi><mo>,</mo><mi mathvariant="normal">M</mi></mrow></msubsup></mrow></semantics></math></inline-formula>) is equal to the rate of accumulation of dopachrome (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi mathvariant="normal">V</mi><mrow><mi>ss</mi></mrow><mrow><mi mathvariant="normal">M</mi><mo>,</mo><mi>DC</mi></mrow></msubsup></mrow></semantics></math></inline-formula>) or to the rate of accumulation of its oxidized adduct, originated by the nucleophilic attack on <i>o</i>-quinone by a nucleophile such as 3-methyl-2-benzothiazolinone (MBTH), (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi mathvariant="normal">V</mi><mrow><mi>ss</mi></mrow><mrow><mi mathvariant="normal">M</mi><mo>,</mo><mrow><mtext> </mtext><mi mathvariant="normal">A</mi></mrow><mo>−</mo><mi>ox</mi></mrow></msubsup></mrow></semantics></math></inline-formula>), despite the existence of coupled reactions. It is shown that the spectrophotometric methods that use MBTH are more useful, as they do not have the restrictions of the L-tyrosine disappearance measurement method, of working at pH = 8 and not having a linear response from 100 μM of L-tyrosine. It is possible to obtain low LOD<sup>M</sup> (limit of detection of the monophenolase activity) values with spectrophotometric methods. The spectrofluorimetric methods had a lower LOD<sup>M</sup> than spectrophotometric methods. In the case of 4-hydroxyphenil-propionic acid, the LOD<sup>M</sup> obtained by us was 0.25 U/mL. Considering the relative sensitivities of 4-hydroxyanisole, compared with 4-hydroxyphenil-propionic acid, LOD<sup>M</sup> values like those obtained by fluorescent methods would be expected. |
topic |
tyrosinase polyphenol oxidase monophenolase activity fluorimetric method spectrophotometric method LOD<sup>M</sup> |
url |
https://www.mdpi.com/2218-273X/11/9/1269 |
work_keys_str_mv |
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doaj-2f8ef4f6fbb84715acdc0087b4d644612021-09-25T23:47:12ZengMDPI AGBiomolecules2218-273X2021-08-01111269126910.3390/biom11091269Considerations about the Continuous Assay Methods, Spectrophotometric and Spectrofluorometric, of the Monophenolase Activity of TyrosinasePablo García-Molina0José Luis Munoz-Munoz1Joaquin A. Ortuño2José Neptuno Rodríguez-López3Pedro Antonio García-Ruiz4Francisco García-Cánovas5Francisco García-Molina6GENZ-Group of Research on Enzymology, Department of Biochemistry and Molecular Biology-A, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Espinardo, 30100 Murcia, SpainMicrobial Enzymology Group, Department of Applied Sciences, University of Northumbria, Ellison Building A, Newcastle Upon Tyne NE1 8ST, UKDepartment of Analytical Chemistry, Faculty of Chemistry, University of Murcia, 30100 Murcia, SpainGENZ-Group of Research on Enzymology, Department of Biochemistry and Molecular Biology-A, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Espinardo, 30100 Murcia, SpainGroup of Chemistry of Carbohydrates, Industrial Polymers and Additives, Department of Organic Chemistry, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Espinardo, 30100 Murcia, SpainGENZ-Group of Research on Enzymology, Department of Biochemistry and Molecular Biology-A, Regional Campus of International Excellence “Campus Mare Nostrum”, University of Murcia, Espinardo, 30100 Murcia, SpainDepartment of Anatomía Patológica, Hospital General Universitario Reina Sofía, Av. Intendente Jorge Palacios, 1, 30003 Murcia, SpainWith the purpose to obtain the more useful tyrosinase assay for the monophenolase activity of tyrosinase between the spectrofluorometric and spectrophotometric continuous assays, simulated assays were made by means of numerical integration of the equations that characterize the mechanism of monophenolase activity. These assays showed that the rate of disappearance of monophenol (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi mathvariant="normal">V</mi><mrow><mi>ss</mi></mrow><mrow><mi mathvariant="normal">M</mi><mo>,</mo><mi mathvariant="normal">M</mi></mrow></msubsup></mrow></semantics></math></inline-formula>) is equal to the rate of accumulation of dopachrome (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi mathvariant="normal">V</mi><mrow><mi>ss</mi></mrow><mrow><mi mathvariant="normal">M</mi><mo>,</mo><mi>DC</mi></mrow></msubsup></mrow></semantics></math></inline-formula>) or to the rate of accumulation of its oxidized adduct, originated by the nucleophilic attack on <i>o</i>-quinone by a nucleophile such as 3-methyl-2-benzothiazolinone (MBTH), (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msubsup><mi mathvariant="normal">V</mi><mrow><mi>ss</mi></mrow><mrow><mi mathvariant="normal">M</mi><mo>,</mo><mrow><mtext> </mtext><mi mathvariant="normal">A</mi></mrow><mo>−</mo><mi>ox</mi></mrow></msubsup></mrow></semantics></math></inline-formula>), despite the existence of coupled reactions. It is shown that the spectrophotometric methods that use MBTH are more useful, as they do not have the restrictions of the L-tyrosine disappearance measurement method, of working at pH = 8 and not having a linear response from 100 μM of L-tyrosine. It is possible to obtain low LOD<sup>M</sup> (limit of detection of the monophenolase activity) values with spectrophotometric methods. The spectrofluorimetric methods had a lower LOD<sup>M</sup> than spectrophotometric methods. In the case of 4-hydroxyphenil-propionic acid, the LOD<sup>M</sup> obtained by us was 0.25 U/mL. Considering the relative sensitivities of 4-hydroxyanisole, compared with 4-hydroxyphenil-propionic acid, LOD<sup>M</sup> values like those obtained by fluorescent methods would be expected.https://www.mdpi.com/2218-273X/11/9/1269tyrosinasepolyphenol oxidasemonophenolase activityfluorimetric methodspectrophotometric methodLOD<sup>M</sup> |