5 research outputs found

    <i>In Cellulo</i> Mapping of Subcellular Localized Bilirubin

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    Bilirubin (BR) is a <i>de novo</i> synthesized metabolite of human cells. However, subcellular localization of BR in the different organelles of human cells has been largely unknown. Here, utilizing UnaG as a genetically encoded fluorescent BR sensor, we report the existence of relatively BR-enriched and BR-depleted microspaces in various cellular organelles of live cells. Our studies indicate that (i) the cytoplasmic facing membrane of the endoplasmic reticulum (ER) and the nucleus are relatively BR-enriched spaces and (ii) mitochondrial intermembrane space and the ER lumen are relatively BR-depleted spaces. Thus, we demonstrate a relationship between such asymmetrical BR distribution in the ER membrane and the BR metabolic pathway. Furthermore, our results suggest plausible BR-transport and BR-regulating machineries in other cellular compartments, including the nucleus and mitochondria

    Focused Fluorescent Probe Library for Metal Cations and Biological Anions

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    A focused fluorescent probe library for metal cations was developed by combining metal chelators and picolinium/quinolinium moieties as combinatorial blocks connected through a styryl group. Furthermore, metal complexes derived from metal chelators having high binding affinities for metal cations were used to construct a focused probe library for phosphorylated biomolecules. More than 250 fluorescent probes were screened for identifying an ultraselective probe for dTTP

    Homogeneous Electrochemical Assay for Protein Kinase Activity

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    Herein, we report a homogeneous assay for protein kinase activity using an electrochemistry-based probe. The approach involves a peptide substrate conjugated with a redox tag and the phosphate-specific receptor immobilized on an electrode surface. The peptide substrate phosphorylated by a protein kinase binds to the receptor site of the probe, which results in a redox current under voltammetric measurement. Our method was successfully applied even in the presence of citrated human blood and modified to enable a single-use, chip-based electrochemical assay for kinase activity

    An Artificial Tongue Fluorescent Sensor Array for Identification and Quantitation of Various Heavy Metal Ions

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    Herein, a small-molecule fluorescent sensor array for rapid identification of seven heavy metal ions was designed and synthesized, with its sensing mechanism mimicking that of a tongue. The photoinduced electron transfer and intramolecular charge transfer mechanism result in combinatorial interactions between sensor array and heavy metal ions, which lead to diversified fluorescence wavelength shifts and emission intensity changes. Upon principle component analysis (PCA), this result renders clear identification of each heavy metal ion on a 3D spatial dispersion graph. Further exploration provides a concentration-dependent pattern, allowing both qualitative and quantitative measurements of heavy metal ions. On the basis of this information, a “safe-zone” concept was proposed, which provides rapid exclusion of versatile hazardous species from clean water samples based on toxicity characteristic leaching procedure standards. This type of small-molecule fluorescent sensor array could open a new avenue for multiple heavy metal ion detection and simplified water quality analysis
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