Current research in the field of single-molecule chemistry is increasingly focused on the development of reliable experimental approaches for investigating chemical processes on a molecular level using single-molecule fluorescence spectroscopy (SMFS). Herein, we report on single-molecule observations of the copper(II)/air mediated oxidation of fluorescently labeled hydroquinone-based probe mole...

The ActVA-ActVB system from Streptomyces coelicolor isatwo-component flavin-dependent monooxygenase that belongs to an emerging class of enzymes involved in various oxidation reactions in microorganisms. The ActVB component is a NADH:flavin oxidoreductase that provides a reduced FMN to the second component, ActVA the proper monooxygenase. In this work, we demonstrate that the ActVA-ActVB system...

NiCu alloy nanoparticle-loaded carbon nanofibers (NiCuCNFs) were fabricated by a combination of electrospinning and carbonization methods. A series of characterizations, including SEM, TEM and XRD, were employed to study the NiCuCNFs. The as-prepared NiCuCNFs were then mixed with laccase (Lac) and Nafion to form a novel biosensor. NiCuCNFs successfully achieved the direct electron transfer of L...

BACKGROUND Exogenous ochronosis is a cutaneous disorder characterized by blue-black or slate-gray hyperpigmentation resulting from the prolonged use of certain topical agents, most commonly hydroquinones. It is notoriously difficult to treat. OBJECTIVE To report the effectiveness of a quality-switched (QS) 755-nm alexandrite laser in treating hydroquinone-induced exogenous ochronosis. METHO...

Unlike lactoperoxidase and horseradish peroxidase, thyroid peroxidase catalyzed the oxidation of hydroquinone mostly by way of 2-electron transfer. This conclusion could be derived from three independent experiments: ESR measurements of p-benzosemiquinone, trapping the unpaired electron by cytochrome c, and spectrophotometric analysis of catalytic intermediates of the enzymes. The 1-electron fl...

Rhodococcus chlorophenolicus PCP-I, a degrader of polychlorinated phenols, guaiacols (2-methoxyphenols), and syringols (2,6-dimethoxyphenols), was shown to O-methylate the degradation intermediate, a chlorinated para-hydroquinone, into 4-methoxyphenol. O-methylation was constitutively expressed, whereas the degradation of chlorophenols and chlorohydroquinones was inducible in R. chlorophenolicu...

The film contained L-cysteine and gold nanoparticles were provided by self-assembled monolayers (SAMs) and potentiostatic electrodeposition technology on the gold electrode. Two methods were used to study the film: In the first, cyclic voltammetry (CV) was used to inspect the functional groups of the film and the same time hydroquinone was chosen to be a probe molecule in the based solution; se...

Cell-suspension cultures of Capsicum annuum L., Solanum aculeatissimum Jacq. and, Datura fastuosa L. (Solanaceae) were established and investigated for the ability to biotransform exogenously-supplied hydroquinone to arbutin. All cultures exhibited good 24-day growth in Murashige and Skoog medium, supplemented with 2,4-dichlorophenoxyacetic acid and benzylaminopurine as plant growth regulators,...

The ultrasound assisted preparation of 1,4-bis(benzyloxy)benzene from the reaction of benzyl chloride (BC) and hydroquinone was carried out successfully using sodium hydroxide and catalyzed by a multi-site phase-transfer catalyst (MPTC) viz., 1,4-dibenzyl-1,4-diazoniabicyclo[2.2.2] octane dichloride in a solid–liquid reaction condition (SL-PTC). Water is only introduced in a trace quantity to t...