Search

Background: Pulp refining is an energy consuming, but integral part of paper production with the aim to increase tensile strength and smoothness of paper sheets. Commercial enzyme formulations are used to lower the energy requirements by pre-treatment of pulp before refining. However, a high number of different commercial enzyme products are available on the market containing enzymes of varying origin and composition, which complicates the prediction of their behavior, especially using different pulp types. Results: Endoglucanase-rich enzyme formulations were characterized regarding enzyme activity at different temperatures, resulting in a significant decrease of activity above 70 °C. Some enzyme preparations additionally contained arabinosidase, xylanase and β-glucosidase activity consequently resulting in a release of xylose and glucose from pulp as determined by high-performance liquid chromatography. Interestingly, one enzyme formulation even showed lytic polysaccharide monooxygenase (LPMO) activity of 3.05 nkat mg−1. A correlation between enzyme activity using the endoglucanase specific derivatized cellopentaose (CellG5) substrate and enzyme performance in laboratory PFI (Papirindustriens forskningsinstitut) refining trials was observed on softwood pulp resulting in a maximum increase in the degree of refining values from 27.7°SR to 32.7°SR. When added to a purified endoglucanase enzyme (31.6°SR), synergistic effects were found for cellobiohydrolase II (34.7°SR) or β-glucosidase enzymes (35.7°SR) in laboratory refining. Comparison with previously obtained laboratory refining results on hardwood pulp allowed differences in enzyme performance based on varying pulp types to be elucidated. Conclusions: Interestingly, the individual enzymes indeed showed different refining effects on softwood and hardwood pulp. This difference could be predicted after development of an adapted enzyme activity assay by combination of the derivatized cellopentaose CellG5 substrate with either softwood or hardwood sulfate pulp. [ABSTRACT FROM AUTHOR]

Dopamine D 1 -like receptors are the most abundant type of dopamine receptors in the central nervous system and, even after decades of discovery, still highly interesting for the study of neurological diseases. We herein describe the synthesis of a new set of fluorescent ligands, structurally derived from D 1 R antagonist SCH-23390 and labeled with two different fluorescent dyes, as tool compounds for the visualization of D 1 -like receptors. Pharmacological characterization in radioligand binding studies identified UR-NR435 (25) as a high-affinity ligand for D 1 -like receptors (pK i (D 1 R)=8.34, pK i (D 5 R)=7.62) with excellent selectivity towards D 2 -like receptors. Compound 25 proved to be a neutral antagonist at the D 1 R and D 5 R in a G s heterotrimer dissociation assay, an important feature to avoid receptor internalization and degradation when working with whole cells. The neutral antagonist 25 displayed rapid association and complete dissociation to the D 1 R in kinetic binding studies using confocal microscopy verifying its applicability for fluorescence microscopy. Moreover, molecular brightness studies determined a single-digit nanomolar binding affinity of the ligand, which was in good agreement with radioligand binding data. For this reason, this fluorescent ligand is a useful tool for a sophisticated characterization of native D 1 receptors in a variety of experimental setups., (© 2023 The Authors. ChemBioChem published by Wiley-VCH GmbH.)

The family of dopamine D 2 -like receptors represents an interesting target for a variety of neurological diseases, e. g. Parkinson's disease (PD), addiction, or schizophrenia. In this study we describe the synthesis of a new set of fluorescent ligands as tools for visualization of dopamine D 2 -like receptors. Pharmacological characterization in radioligand binding studies identified UR-MN212 (20) as a high-affinity ligand for D 2 -like receptors (pK i (D 2long R)=8.24, pK i (D 3 R)=8.58, pK i (D 4 R)=7.78) with decent selectivity towards D 1 -like receptors. Compound 20 is a neutral antagonist in a G o1 activation assay at the D 2long R, D 3 R, and D 4 R, which is an important feature for studies using whole cells. The neutral antagonist 20, equipped with a 5-TAMRA dye, displayed rapid association to the D 2long R in binding studies using confocal microscopy demonstrating its suitability for fluorescence microscopy. Furthermore, in molecular brightness studies, the ligand's binding affinity could be determined in a single-digit nanomolar range that was in good agreement with radioligand binding data. Therefore, the fluorescent compound can be used for quantitative characterization of native D 2 -like receptors in a broad variety of experimental setups., (© 2023 The Authors. ChemBioChem published by Wiley-VCH GmbH.)

Radioligands used previously for histamine H 3 receptor (H 3 R) are accompanied by a number of disadvantages. In this study, we report the synthesis of the new H 3 R radioligand [ 3 H]UR-MN259 ([ 3 H] 11 ) with high (radio)chemical purity and stability. The radioligand exhibits sub-nanomolar affinity for the target receptor (p K i (H 3 R) = 9.56) and displays an outstanding selectivity profile within the histamine receptor family (>100,000-fold selective). [ 3 H]UR-MN259 is ideally suitable for the characterization of H 3 R ligands in competition binding and shows one-site binding to the H 3 R in saturation binding experiments. The radiotracer shows fast association to the receptor (τ assoc = 6.11 min), as well as full dissociation from the receptor (τ dissoc = 14.48 min) in kinetic binding studies. The distinguished profile of [ 3 H]UR-MN259 makes it a highly promising pharmacological tool to further investigate the role of the H 3 R in the CNS., Competing Interests: The authors declare no competing financial interest., (© 2023 The Authors. Published by American Chemical Society.)

The histamine H 3 receptor (H 3 R) is considered an attractive drug target for various neurological diseases. We here report the synthesis of UR-NR266, a novel fluorescent H 3 R ligand. Broad pharmacological characterization revealed UR-NR266 as a sub-nanomolar compound at the H 3 R with an exceptional selectivity profile within the histamine receptor family. The presented neutral antagonist showed fast association to its target and complete dissociation in kinetic binding studies. Detailed characterization of standard H 3 R ligands in NanoBRET competition binding using UR-NR266 highlights its value as a versatile pharmacological tool to analyze future H 3 R ligands. The low nonspecific binding observed in all experiments could also be verified in TIRF and confocal microscopy. This fluorescent probe allows the highly specific analysis of native H 3 R in various assays ranging from optical high throughput technologies to biophysical analyses and single-molecule studies in its natural environment. An off-target screening at 14 receptors revealed UR-NR266 as a selective compound.