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Petit GA. Adjusting the Fitting of Fluorescence-Based Dose-Response Kinase Inhibition Assay to Account for Fluorescent Inhibitors. Assay Drug Dev Technol 2023; 21:331-336. [PMID: 37768806 DOI: 10.1089/adt.2023.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2023] Open
Abstract
Fluorescence is routinely used to monitor kinase inhibition in commercial assays. Occasionally fluorescent compounds can interfere with the fluorescent reading. To address this issue, the problematic data are usually truncated to improve the fit, however, this approach raises ethical and reproducibility concerns. Instead, it is suggested to adjust the fitting formula, to account for the autofluorescence of the compounds and improve the fit of the data compared with a naive approach. Finally, it was noticed that truncating the data can result in a small underestimation of the IC50 values and should therefore be used carefully.
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Jiménez-Nava RA, Zepeda-Vallejo LG, Santoyo-Tepole F, Chávez-Camarillo GM, Cristiani-Urbina E. RP-HPLC Separation and 1H NMR Identification of a Yellow Fluorescent Compound-Riboflavin (Vitamin B 2)-Produced by the Yeast Hyphopichia wangnamkhiaoensis. Biomolecules 2023; 13:1423. [PMID: 37759822 PMCID: PMC10527106 DOI: 10.3390/biom13091423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 09/29/2023] Open
Abstract
The yeast Hyphopichia wangnamkhiaoensis excretes a brilliant yellow fluorescent compound into its growth culture. In this study, we isolated and identified this compound using reverse-phase high-performance liquid chromatography-diode array detector (RP-HPLC-DAD) as well as 1H NMR and UV-Vis spectroscopy. Two of the three RP-HPLC-DAD methods used successfully separated the fluorescent compound and involved (1) a double separation step with isocratic flow elution, first on a C18 column and later on a cyano column, and (2) a separation with a linear gradient elution on a phenyl column. The wavelengths of maximum absorption of the fluorescent compound-containing HPLC fractions (~224, 268, 372, and 446 nm) are in good agreement with those exhibited by flavins. The 1H NMR spectra revealed methyl (δ 2.30 and 2.40) and aromatic proton (δ 7.79 and 7.77) signals of riboflavin. The 1H NMR spectra of the samples spiked with riboflavin confirmed that the brilliant yellow fluorescent compound is riboflavin. The maximum excitation and emission wavelengths of the fluorescent compound were 448 and 528 nm, respectively, which are identical to those of riboflavin.
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Affiliation(s)
- Raziel Arturo Jiménez-Nava
- Departamento de Ingeniería Bioquímica, Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Avenida Wilfrido Massieu s/n, Unidad Profesional Adolfo López Mateos, Ciudad de Mexico 07738, Mexico
- Departamento de Microbiología, Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Prolongación de Carpio y Plan de Ayala s/n, Colonia Santo Tomás, Ciudad de Mexico 11340, Mexico
| | - Luis Gerardo Zepeda-Vallejo
- Departamento de Química Orgánica, Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Prolongación de Carpio y Plan de Ayala s/n, Colonia Santo Tomás, Ciudad de Mexico 11340, Mexico
| | - Fortunata Santoyo-Tepole
- Departamento de Microbiología, Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Prolongación de Carpio y Plan de Ayala s/n, Colonia Santo Tomás, Ciudad de Mexico 11340, Mexico
- Departamento de Investigación, Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Prolongación de Carpio y Plan de Ayala s/n, Colonia Santo Tomás, Ciudad de Mexico 11340, Mexico
| | - Griselda Ma. Chávez-Camarillo
- Departamento de Microbiología, Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Prolongación de Carpio y Plan de Ayala s/n, Colonia Santo Tomás, Ciudad de Mexico 11340, Mexico
| | - Eliseo Cristiani-Urbina
- Departamento de Ingeniería Bioquímica, Instituto Politécnico Nacional, Escuela Nacional de Ciencias Biológicas, Avenida Wilfrido Massieu s/n, Unidad Profesional Adolfo López Mateos, Ciudad de Mexico 07738, Mexico
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