Oxygen scavenger system

Falahee, M. B., Park, S. F., and Adams, M. R. (2003). Detection and enumeration of Campylobacter jejuni and Campylobacter coli by indirect impedimetry with an oxygen scavenging system. /. Food Prot. 66,1724-1726. 

Cytochrome P-450 from rat or human liver microsome preparations is inactivated when incubated anaerobically with carbon tetrachloride in the presence of NADPH and an oxygen-scavenging system (Manno et al. 1988 1992). Inactivation involved destruction of the heme tetrapyrrolic structure, and followed pseudo first-order kinetics with fast and slow half lives of 4.0 and 29.8 minutes. When compared with rat liver microsomes, the human preparations were 6-7 times faster at metabolizing carbon tetrachloride, and only about one- eighth as susceptible to suicide inactivation (about 1 enzyme molecule lost for every 196 carbon tetrachloride molecules metabolized). 

Alternatively, the RNA can be immobilized on a shde, in which case single molecules can be studied for many seconds and conformational transitions observed. The time of observation is limited by photochemical effects on the fluorophores, but this can be extended with recently improved oxygen scavenging systems (Aitken et al., 2008 Rasnik et al., 2006). Again there are two choices. A wide-held approach can be used,... 

Aitken, C. E., Marshall, R. A., and Pughsi, J. D. (2008). An oxygen scavenging system for improvement of dye stability in single-molecule fluorescence experiments. Biophys.J. 94, 1826-1835. 

One of the most interesting papers on ascorbic acid-Cu reactions showed that ascorbic acid-Cu catalyzes the formation of ethylene from several precursors. The interest in ethylene was as an abscission agent in plants. All alcohols, aldehydes, acids, ethers, and epoxides formed ethylene when mixed with Cu and ascorbic acid in 5-mL closed bottles at 30 °C for 1 h. Methional was the most active, followed by propanal, propanol, propyl ether, ethyl ether, and ethanol. This reaction may be part of the oxygen scavenging system because Cu increases ascorbic acid s ability to scavenge oxygen. The authors claim this reaction cannot be attributed to copper in its lower valence state. 

Using polyolefins in food packaging has many challenges to improve the surface properties of materials maintaining their excellent bulk properties. Improvement in oxygen scavenging systems needs to be improved also to reduce the oxidation of the food and the presence of aerobic bacteria and mold growth. 

Ozone has been shown to inhibit photosynthesis (8-10) and cause changes in the chloroplastic activated oxygen scavenging system (3, 11) implying action at the chloroplast level. 

The active-oxygen scavenging system in plants consists of five enzymes si )eroxide dismutase (SOD), glntathlcaie reductase, dehydroascorbate reductase, monod ydroascorbate reductase, and ascorbate peroxidase (reviewed in 8). 

Oxygen-scavenger system Oxidizable polymer Catalyst Compatibilizer... 

Polymers Corference Proceedings (Atlanta, GA, 10th-12th Oct. 1898), p. 7-18 A.L. Brody, E.R. Strupinsky, L.R. Kline, Oxygen scavenger systems, in Active Packaging for Food Applications (Technomic Publishing, Pennsylvania, 2001)... 

Rodgers, B. D. and Compton, L. New polymeric oxygen scavenging system for coextruded packaging structures. The Proceedings of Oxygen Absorbers 2001 and Beyond Conference. 

Removing oxygen from the sample by the oxygen scavenging system decreases the chance of the fluorophores to irreversibly photobleach. If the fluorophores seem to bleach too rapidly, try with fresh oxygen scavenger system. 

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