Quinizarin diester is used as a fluoro-chromogenic substrate of the activity of lipase supported in poly(methylmetacrylate) beads (CALB, Novozym 435) dispersed in organic solvents. The monoester and diester of quinizarin are both non-fluorescent species contrasting with the enzymatic product quinizarin that shows optical absorption in the visible region and strong fluorescence signal. The enzymatic conversion is accomplished by spectroscopic measurements and it follows a sigmoid curve from which the mean reaction time of the enzymatic process can be determined. This parameter indicates the enzyme activity of the immobilized lipase. Its dependency with the amount of lipase allowed the determination of the ratio of the catalytic rate and the Michaelis constant (/) and the experimental value found was (1.0 ± 0.1) × 10 mg/min in the case of quinizarin diacetate.
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http://dx.doi.org/10.3390/molecules22122136 | DOI Listing |
Luminescence
January 2025
College of Environmental Science and Engineering, Guilin University of Technology, Guilin, China.
It is of great significance to develop sensors for trace pesticide residues detection in food. Herein, an electrochemiluminescence (ECL) sensor with high sensitivity for the detection of methyl parathion (MP) was constructed by combining of the acetylcholinesterase (AChE) enzyme-inhibited reaction with tris-2,2'-bipyridyl ruthenium Ru(bpy) -triethylamine (TEA) system for the first time. A new ECL probe of MIL-100 loaded with Ru(bpy) (Ru-MIL-100) was synthesized, and then Ru-MIL-100 and AChE were immobilized on the electrode with Nafion.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Department of Pharmaceutical Technology, National Institute of Pharmaceutical Education and Research (NIPER) S.A.S. Nagar, Mohali, Punjab 160062, India. Electronic address:
Customized nano-biocatalysts of laccase have been made using nano-structured polyaniline viz. nano-fibers and nano-tubes, as immobilization supports and a simultaneous comparison between them has been made. Laccases are poly-phenol oxidases having tremendous utility concerning wider areas of application especially in the field of organic and drug syntheses.
View Article and Find Full Text PDFBehav Brain Res
January 2025
Experimental Biology Center, University of Fortaleza, Av. Washington Soares, 1321, Fortaleza, Ceará, Brazil; Laboratory of Bioprospection of Natural Products and Biotechnology, Department of Chemistry, CECITEC/UECE - Center for Education, Science and Technology of the Inhamuns Region. R. Seis, 15 - Bezerra de Sousa, Tauá, Ceará, Brazil. Electronic address:
Mimosa tenuiflora ("jurema-preta") is traditionally used in folk medicine for various diseases. The study investigated the neuropharmacological potential of Mimosa tenuiflora bark fraction (FATEM) in adult zebrafish. This included the acute toxicity (LC50) of FATEM (0.
View Article and Find Full Text PDFACS Nano
January 2025
Mechanobiology Institute, National University of Singapore, Singapore 117411, Singapore.
Transmembrane signaling receptors, such as integrins, organize as nanoclusters that provide several advantages, including increasing avidity, sensitivity (increasing the signal-to-noise ratio), and robustness (signaling threshold) of the signal in contrast to signaling by single receptors. Furthermore, compared to large micron-sized clusters, nanoclusters offer the advantage of rapid turnover for the disassembly of the signal. However, whether nanoclusters function as signaling hubs remains poorly understood.
View Article and Find Full Text PDFHeliyon
December 2024
Department of Dyes and Chemical Engineering, Bangladesh University of Textiles, Dhaka, 1208, Bangladesh.
Silver nanoparticles (AgNPs) have attracted significant interest in recent years owing to their unique physicochemical properties, including antimicrobial reduction capabilities, photocatalytic activity, self-cleaning features, superhydrophobicity, and electrical conductivity. Their characteristics render them highly advantageous for various textile, electronics, food and agriculture, water treatment, and biomedical applications. This detailed analysis explores the recent benefits and drawbacks of various synthesis methods, immobilization techniques, and characterization of AgNPs while emphasizing novel strategies that improve their functionality across different substrates.
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