The kinetic mechanism of enzymatic modification of flavonol quercetin with L-cysteine by horseradish peroxidase (HRP) was studied. Reaction of modification of quercetin was followed by recording spectral changes over time at 380 nm. All reactions were performed in 100 mM phosphate buffer pH, 6.0 at 20 degrees C. Kinetic parameters were determined from graphics of linear Michaelis-Menten equatio...

Based on our previous findings, the present study has focused on free-radical-mediated degradation of the synovial biopolymer hyaluronan. The degradation was induced in vitro by the Weissberger's system comprising ascorbate plus cupric ions in the presence of oxygen, representing a model of the early phase of acute synovial joint inflammation. The study presents a novel strategy for hyaluronan ...

The coenzyme function of pyridoxal-phosphate in cysteine desulfhydration and in the mechanistically similar serine and threonine dehydration (deamination) processes has been a subject of discussion in a number of recent publications (see, for example, Snell, 1952, and Braunstein and Shemyakin, 1953). A chemical model reaction has been proposed (Metzler and Snell, 1952). Evidence for pyridoxal-p...

Cysteine is an essential requirement in living organisms. However, due to its reactive thiol side chain, elevated levels of intracellular cysteine can be toxic and therefore need to be rapidly eliminated from the cellular milieu. In mammals and many other organisms, excess cysteine is believed to be primarily eliminated by the cysteine dioxygenase dependent oxidative degradation of cysteine, fo...

Abstract l -Cysteine coated zinc oxide (ZnO) nano hollow spheres were prepared as a potent drug delivery agent to eradicate Salmonella enterica serovar Typhimurium ( S. typhimurium ). The ZnO synthesized by following the environmentally-friendly trisodium citrate assisted method and -cysteine (L-Cys) conjugate with its surface. ZnO/L-Cys@CFX nanocarrier has been fabricated incorporating ceftizo...

Tissue contents and urinary excretion of taurine were studied in rats after the administration of L-cysteine and its derivatives. Average taurine content in the liver of rats fed a 25% casein diet for 7 days increased 2-fold 2h after the intraperitoneal administration of 5 mmol of L-cysteine per kg of body weight, whereas that in rats fed a 5% casein diet for 2 days increased only slightly. The...

L-cysteine is a food additive that used in bakery ingredient. It as stabilizer to soften the texture of dough. However, primary sources could be controversial it might derive from animal and human parts. This study aimed differentiate by using Attenuated Total Reflection Fourier Transform Infrared (ATR-FTIR) Raman spectroscopy. Raw materials pig bristles, hair, cow horn, duck feather chicken we...

Yu A.-N., Tang L.-P. (2016): Kinetics of non-enzymatic browning reaction from the l-ascorbic acid/l-cysteine model system. Czech J. Food Sci., 34: 503–510. The kinetics of the non-enzymatic browning reaction from l-ascorbic acid/l-cysteine model systems was investigated at 125–155°C for 10–120 min by measuring the loss of reactants and monitoring the brown colour development. The result showed ...

On annealing at temperatures near 100 degrees C, carbon-centered radicals migrate to sulfur-centered radicals in X-irradiated crystals of L-alpha-amino-n-butyric acid hydrochloride, CH3CH2CH(NH3-Cl)COOH, containing L-cysteine hydrochloride, SHCH2CH(NH3Cl)COOH. Samples containing 0, 0.5, 1.0, and 1.5% L-cysteine hydrochloride were studied. When no cysteine is present, the carbon-centered radical...