Considerations about the Continuous Assay Methods, Spectro-Photometric and Spectrofluorometric, of the Monophenolase Activity of Tyrosinase

García-Molina, Pablo, Munoz, Jose, Ortuño, Joaquin A., Rodríguez-López, José Neptuno, García-Ruiz, Pedro Antonio, García-Cánovas, Francisco and García-Molina, Francisco (2021) Considerations about the Continuous Assay Methods, Spectro-Photometric and Spectrofluorometric, of the Monophenolase Activity of Tyrosinase. Biomolecules, 11 (9). p. 1269. ISSN 2218-273X

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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 () is equal to the rate of accumulation of dopachrome () or to the rate of accumulation of its oxidized adduct, originated by the nucleophilic attack on o-quinone by a nucleophile such as 3-methyl-2-benzothiazolinone (MBTH), (), 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 LODM (limit of detection of the monophenolase activity) values with spectrophotometric methods. The spectrofluorimetric methods had a lower LODM than spectrophotometric methods. In the case of 4-hydroxyphenil-propionic acid, the LODM obtained by us was 0.25 U/mL. Considering the relative sensitivities of 4-hydroxyanisole, compared with 4-hydroxyphenil-propionic acid, LODM values like those obtained by fluorescent methods would be expected.

Item Type: Article
Additional Information: Funding information: Fundacion Séneca, the Region de Murcia (FS‐RM) (20809/PI/18). J.M.‐M.receive funding from internal grants in Northumbria University.
Uncontrolled Keywords: Tyrosinase; polyphenol oxidase; monophenolase activity; fluorimetric method; spectrophotometric method; LODM
Subjects: C500 Microbiology
C700 Molecular Biology, Biophysics and Biochemistry
Department: Faculties > Health and Life Sciences > Applied Sciences
Depositing User: Elena Carlaw
Date Deposited: 25 Aug 2021 13:29
Last Modified: 25 Aug 2021 13:31

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