Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Ultrafiltration digest

Mechanism-based inactivation results in formation of a covalent adduct between the active inhibitor and the enzyme, or between the active inhibitor and a substrate or cofactor molecule. If the mechanism involves covalent modification of the enzyme, then one should not be able to demonstrate a recovery of enzymatic activity after dialysis, gel filtration, ultrafiltration, or large dilution, as described in Chapters 5 to 7. Additionally, if the inactivation is covalent, denaturation of the enzyme should fail to release the inhibitory molecule into solution. If a radiolabeled version of the inactivator is available, one should be able to demonstrate irreversible association of radioactivity with the enzyme molecule even after denaturation and separation by gel filtration, and so on. In favorable cases one should likewise be able to demonstrate covalent association of the inhibitor with the enzyme by a combination of tryptic digestion and LC/MS methods. [Pg.230]

We have tried two non-destructive approaches to fractionation of the mineral complexes in in vitro digests ultrafiltration and gel filtration. Only preliminary data from gel filtration experiments are currently available. [Pg.13]

Table IV. Fractionation of Calcium in an In Vitro Digest by Centrifugation (CE) and Ultrafiltration (UF) and Comparison with UF Results for CaCl2... Table IV. Fractionation of Calcium in an In Vitro Digest by Centrifugation (CE) and Ultrafiltration (UF) and Comparison with UF Results for CaCl2...
Fractionation Methods. Ultrafiltration and gel filtration are nondestructive methods which, based on limited experience, can be used for fractionation of mineral complexes from digests. In earlier studies mineral absorption on the gel material was a problem. Lonnerdal (30) introduced a method of treating dextran gels with sodium borohydride in order to eliminate the mineral-binding sites on the gel. In preliminary studies we have recovered more than 90 of Ca, Mg, Fe, Zn and P in samples applied to a borohydride-treated gel column (Sephadex G-50, Pharmacia Fine Chemicals, Piscataway, NJ). Recovery of Ca (Table IV) and Mg, Fe and Zn from ultrafiltration was also good. [Pg.19]

In our experience with ultrafiltration, use of C02 pressure to force the filterable material through the membrane in the ultrafiltration procedure introduced a possible source of error. The high pressure caused more CO2 to be dissolved in the digest supernatant and the pH in the chamber decreased to about 6.2. This may have caused a shift of the mineral among ligands (31). It should be possible to formulate a mixture of CO2 and N2 to maintain the pH in the chamber, but we have not pursued this. [Pg.19]

Gel filtration may be best used to analyze fractions already separated from a digest supernatant by ultrafiltration, as used in a recent study by Sandstrom, et al. (3.2). A more precise separation of complexes can be obtained with gel filtration, but the size of sample which can be applied is limited. Thus, in many situations, the sample must be concentrated before being applied to the gel column. Either pre-purification or sample concentration could introduce possible shifts in mineral binding which should be understood for proper interpretation of the results (33). [Pg.20]

Prq[iaration of clarified digests sludge. Samples were removed under anaerobic conditions and moved immediately into the anaerobic chamber. Before analysis, the samples were clarified by centrifugation and filtration with 0.22-jLtm Acrodisc filters. Concentrated digester supernatant was also examined, and it was prepared by ultrafiltration in the anaerobic chamber with an Amicon stirred cell ultraconcentrator and Amicon PMIO membranes. [Pg.28]

It is a key step to develop methods to separate peptides with different molecular weights. An ultrafiltration membrane system equipped with the appropriate molecular weight cutoff has been effectively used in separating peptides having desired molecular weights (Jeon et al., 2000). In order to obtain functionally active peptides, it is a common method to use the type of enzymes letting sequential enzymatic digestions. [Pg.239]

As has been described above, HA is an essential functional component of almost all tissues in the vertebrate organism. Thus, various animal tissues - e.g. rooster combs, shark skin, bovine eyeballs - have been used as sources of isolation and production of high molar mass HAs. Since in the biological materials HA is usually present in a complex linked to other biopolymers, several separation procedures have to be applied in order to obtain a pure compound, such as protease digestion, HA ion-pair precipitation (with e.g. cetylpyridinium chloride), membrane ultrafiltration, HA non-solvent precipitation and/or lyophilization [135,136]. The mean molar mass of the commercially available extractive HA preparations obtained from animal tissues is mostly in the range from several hundred thousands Da up to approximately 2.5 MDa. To date, the demand for HA materials approved for applications in human medicine has been satisfied by high molar mass HAs prepared from the rooster combs. For example, Healon (Pharmacia Upjohn, Inc., Peapack, NJ, USA) - used in viscosurgery at eye implant insertion - has a mean HA molar mass of about 2.5 MDa. [Pg.812]

Macromolecular substrates such as proteins offer unique opportunities in processing modes with enzymes. Ultrafiltration membrane reactors (10) can be used to retain the protein substrate and the proteolytic enzyme in the reactor, while the hydrolytic products escape through the membrane to be collected. Using an ultrafiltration reactor, Cheftel (11) was able to solubilize 95% of FPC in 24 hr using pronase digestion. [Pg.190]

Yasotha, K., Aroua, M.K., Ramachandran, K.B. and Tan, l.K.P. (2006) Recovery of medium-chain-length polyhydroxyalkanoates (PHAs) through enzymatic digestion treatments and ultrafiltration. Biochemical Engineering Journal, 30, 260-268. [Pg.167]

Ammonium bicarbonate or Tris-HCl need to be removed from any digest solutions before metal-ion affinity chromatography is performed. Primary or secondary amines compete for the iron on sample loading. Ultrafiltration and gel filtration are appropriate techniques for exchanging these buffer components. [Pg.396]

Wallberg O, Jonsson A-S. Separation of lignin in kraft cooking liquor from a continuous digester by ultrafiltration at temperatures above 100°C. Desalination 2006 195(1—3) 187—200. [Pg.122]

The application of ultrafiltration membranes, which are currently all of a polymeric nature, is more widespread because it is possible to separate smaller molecules such as sugars from larger molecules such as proteins. The main attraction for ultrafiltering cheese milk is the increased yield that results from the incorporation of whey protein into the cheese. In a traditional process these proteins remain in the waste liquid whey. The waste stream from a membrane unit still contains lactose (milk sugar) and this can be used for alcohol production, as an animal feed or as a feed to an anaerobic digester which will produce methane. The technology is being applied to both hard and soft cheese examples includes Cheddar and Camembert. [Pg.107]


See other pages where Ultrafiltration digest is mentioned: [Pg.191]    [Pg.191]    [Pg.209]    [Pg.30]    [Pg.13]    [Pg.157]    [Pg.49]    [Pg.50]    [Pg.251]    [Pg.9]    [Pg.403]    [Pg.293]    [Pg.374]    [Pg.385]    [Pg.386]    [Pg.990]    [Pg.2360]    [Pg.2363]    [Pg.192]    [Pg.198]    [Pg.114]    [Pg.404]    [Pg.37]    [Pg.10]    [Pg.277]    [Pg.135]    [Pg.128]    [Pg.124]    [Pg.113]    [Pg.145]    [Pg.287]    [Pg.90]    [Pg.92]    [Pg.93]    [Pg.156]    [Pg.287]   
See also in sourсe #XX -- [ Pg.11 ]




SEARCH



Ultrafiltrate

© 2024 chempedia.info