Search results for "Phenylthiourea"
showing 7 items of 7 documents
Global diversity in the TAS2R38 bitter taste receptor: revisiting a classic evolutionary PROPosal
2016
AbstractThe ability to taste phenylthiocarbamide (PTC) and 6-n-propylthiouracil (PROP) is a polymorphic trait mediated by the TAS2R38 bitter taste receptor gene. It has long been hypothesized that global genetic diversity at this locus evolved under pervasive pressures from balancing natural selection. However, recent high-resolution population genetic studies of TAS2Rs suggest that demographic events have played a critical role in the evolution of these genes. We here utilized the largest TAS2R38 database yet analyzed, consisting of 5,589 individuals from 105 populations, to examine natural selection, haplotype frequencies and linkage disequilibrium to estimate the effects of both selectio…
Phenoloxidase-dependent cytotoxic mechanism in ascidian (Styela plicata) hemocytes active against erythrocytes and K562 tumor cells.
1997
The cytotoxic activity against rabbit erythrocytes (RE) and human K562 tumor cells by Styela plicata hemocytes was significantly related to the phenoloxidase (PO) which converts phenols to quinone and initiates the melanogenic pathway. The effector hemocyte population, separated in a Percoll density gradient band, enriched in a granulocyte type named "morula cells", was examined with RE in a hemocyte cytotoxic assay and plaque forming cell assay. Inhibition experiments with the copper chelating agents 1-phenyl-2-thiourea and tropolone, the substrate analogue sodium benzoate and sodium ascorbate support the notion that hemocyte cytotoxic activity is a PO-dependent mechanism. Treatments of he…
CCDC 2081478: Experimental Crystal Structure Determination
2021
Related Article: Nele Konrad, Matvey Horetski, Mariliis Sihtm��e, Khai-Nghi Truong, Irina Osadchuk, Tatsiana Burankova, Marc Kielmann, Jasper Adamson, Anne Kahru, Kari Rissanen, Mathias O. Senge, Victor Borovkov, Riina Aav, Dzmitry Kananovich|2021|Chemosensors|9|278|doi:10.3390/chemosensors9100278
CCDC 2061188: Experimental Crystal Structure Determination
2021
Related Article: Lauri Happonen, J. Mikko Rautiainen, Arto Valkonen|2021|Cryst.Growth Des.|21|3409|doi:10.1021/acs.cgd.1c00183
CCDC 2061196: Experimental Crystal Structure Determination
2021
Related Article: Lauri Happonen, J. Mikko Rautiainen, Arto Valkonen|2021|Cryst.Growth Des.|21|3409|doi:10.1021/acs.cgd.1c00183
Kinetic properties of hexameric tyrosinase from the crustacean Palinurus elephas.
2008
Tyrosinases catalyze hydroxylation of monophenols to o-diphenols and their subsequent oxidation to o-quinones, whereas catecholoxidases catalyze only the latter reaction. Both enzymes occur in all organisms and are Type 3 copper proteins that perform the first steps of melanin formation. In arthropods, they play an essential role in the sclerotization of the exoskeleton. Very few phenoloxidases are characterized structurally or kinetically and the existence of an actual tyrosinase activity has not been demonstrated in most cases. Here we present for the first time a complete kinetic characterization of a tyrosinase from a crustacean (Palinurus elephas) including the influence of inhibitors.…
Purification and spectroscopic studies on catechol oxidases from Lycopus europaeus and Populus nigra: evidence for a dinuclear copper center of type …
1999
We purified two catechol oxidases from Lycopus europaeus and Populus nigra which only catalyze the oxidation of catechols to quinones without hydroxylating tyrosine. The molecular mass of the Lycopus enzyme was determined to 39,800 Da and the mass of the Populus enzyme was determined to 56,050 Da. Both catechol oxidases are inhibited by thiourea, N-phenylthiourea, dithiocarbamate, and cyanide, but show different pH behavior using catechol as substrate. Atomic absorption spectrosopic analysis found 1.5 copper atoms per protein molecule. Using EPR spectroscopy we determined 1.8 Cu per molecule catechol oxidase. Furthermore, EPR spectroscopy demonstrated that catechol oxidase is a copper enzym…