A spectrophotometric method for the quantification of an enzyme activity producing 4-substituted phenols: Determination of toluene-4-monooxygenase activity

Nolan, Louise C.; O’Connor, Kevin E.

doi:10.1016/j.ab.2005.05.032

Cited by 8 publications

(6 citation statements)

References 32 publications

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“…Considering the high reactivity and instability of intermediates and the interference of external factors (such as temperature and oxygen), many other assays are subsequently improved. Many nucleophiles start appearing on the stage by capturing highly reactive DQ as stable-colored products [59]. Under acidic conditions, MBTH generate a pink adduct with high molar absorptivity and solubility, whose clear stoichiometry and high stability endow great measurability [42,44,60].…”

Section: Spectrophotometric Assaysmentioning

confidence: 99%

Spectrophotometric Assays for Sensing Tyrosinase Activity and Their Applications

et al. 2021

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Tyrosinase (TYR, E.C. 1.14.18.1), a critical enzyme participating in melanogenesis, catalyzes the first two steps in melanin biosynthesis including the ortho-hydroxylation of L-tyrosine and the oxidation of L-DOPA. Previous pharmacological investigations have revealed that an abnormal level of TYR is tightly associated with various dermatoses, including albinism, age spots, and malignant melanoma. TYR inhibitors can partially block the formation of pigment, which are always used for improving skin tone and treating dermatoses. The practical and reliable assays for monitoring TYR activity levels are very useful for both disease diagnosis and drug discovery. This review comprehensively summarizes structural and enzymatic characteristics, catalytic mechanism and substrate preference of TYR, as well as the recent advances in biochemical assays for sensing TYR activity and their biomedical applications. The design strategies of various TYR substrates, alongside with several lists of all reported biochemical assays for sensing TYR including analytical conditions and kinetic parameters, are presented for the first time. Additionally, the biomedical applications and future perspectives of these optical assays are also highlighted. The information and knowledge presented in this review offer a group of practical and reliable assays and imaging tools for sensing TYR activities in complex biological systems, which strongly facilitates high-throughput screening TYR inhibitors and further investigations on the relevance of TYR to human diseases.

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Section: Spectrophotometric Assaysmentioning

confidence: 99%

Spectrophotometric Assays for Sensing Tyrosinase Activity and Their Applications

et al. 2021

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“…Nolan and O’Connor applied the assay for the quantification of a toluene-4-monooxygenase activity producing para -substituted phenols. These were detected after tyrosinase-assisted transformation of the products to 4-substituted catechols …”

Section: Chromo- and Fluorogenic Probes For Phenolsmentioning

confidence: 99%

Enlightening the Path to Protein Engineering: Chemoselective Turn-On Probes for High-Throughput Screening of Enzymatic Activity

et al. 2023

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Many successful stories in enzyme engineering are based on the creation of randomized diversity in large mutant libraries, containing millions to billions of enzyme variants. Methods that enabled their evaluation with high throughput are dominated by spectroscopic techniques due to their high speed and sensitivity. A large proportion of studies relies on fluorogenic substrates that mimic the chemical properties of the target or coupled enzymatic assays with an optical read-out that assesses the desired catalytic efficiency indirectly. The most reliable hits, however, are achieved by screening for conversions of the starting material to the desired product. For this purpose, functional group assays offer a general approach to achieve a fast, optical read-out. They use the chemoselectivity, differences in electronic and steric properties of various functional groups, to reduce the number of false-positive results and the analytical noise stemming from enzymatic background activities. This review summarizes the developments and use of functional group probes for chemoselective derivatizations, with a clear focus on screening for enzymatic activity in protein engineering.

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“…and heterocyclic bases 5 , MBTH (3-Methyl 1, 2-Benzothiazolinehy-drazone hydrochloride) is also used in the analysis of several compounds of biochemical 6 , pharmaceutical 7 and insecticidal 8 . MBTH responds to the enzymatic activity of some of the enzymes like peroxidase 9 , lactase 10 alcohol oxidase 11 and toluene-4-monooxygenase 12 in the presence of corresponding substrates. The present study documents an accurate, sensitive, rapid, selective and reproducible visible spectrophotometric assay which meets an accepted analytical validation.…”

Section: Research Articlementioning

confidence: 99%

Spectrophotometric Estimation of Gemcitabine HCl in Pharmaceutical Dosage form via Oxidative Coupling Reaction

2015

Chem Sci Trans

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Gemcitabine HCl is an antiviral drug, novel, facile, sensitive and selective spectrophotometric method have been developed for the quantitative estimation of gemcitabine HCl in pharmaceutical formulations with coupling reagent. The proposed method involves the oxidative coupling reaction of gemcitabine HCl with 3-methyl-2-benzothiazolinone hydrazone hydrochloride monohydrate in the presence of ferric chloride and acidic medium to form bluish green colored chromogen at 558 nm. There is no interference observed from the excipients that are present in the Gemcitabine HCl pharmaceutical dosage form with this estimation. The optimum reaction conditions and other important analytical parameters were established.

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A spectrophotometric method for the quantification of an enzyme activity producing 4-substituted phenols: Determination of toluene-4-monooxygenase activity

Cited by 8 publications

References 32 publications

Spectrophotometric Assays for Sensing Tyrosinase Activity and Their Applications

Spectrophotometric Assays for Sensing Tyrosinase Activity and Their Applications

Enlightening the Path to Protein Engineering: Chemoselective Turn-On Probes for High-Throughput Screening of Enzymatic Activity

Spectrophotometric Estimation of Gemcitabine HCl in Pharmaceutical Dosage form via Oxidative Coupling Reaction

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