Charcoal protein adsorption

Adsorption on finely divided inert materials. These materials offer a large surface area for interaction with protein. Adsorption of protein on charcoal, a nonpolar substance, presumably occurs by hydrophobic interaction and can be used to separate proteins from a fluid matrix. Adsorption on polar substances such as silica, alumina, or hydroxyapatite depends on ionic interactions or hydrogen bonding these substances can be used with buffer elution in chromatographic separations. 

Immobilization of proteins (adsorption of invertase on activated charcoal) reported for the first... 

First report on the immobilization of proteins adsorption of invertase to activated charcoal [1]... 

First report on tiie immobilization of proteins Adsorption of invertase to activated charcoal J. M. Nelson and E. G. Griffin... 

Separation of bound and free analyte. This is often done by adsorption of the free analyte on activated charcoal or precipitation of the protein bound fraction with ammonium sulphate. 

Adrenal Tumours The assay-method is entirely based on the Schwartz-Mann Kit. According to this method, cortisol is first extracted from the plasma using CH2C12 (methylene chloride). In the actual radioimmunoassay the cortisol present in the extract competes with Cortisol-H3 i.e., the radioactive tracer) for the common binding sites on transcortin, which is incidently not an antibody but a cortisol-binding protein. Now, the free cortisol is quantitatively removed by adsorption on dextran-coated charcoal from the one bound to the transcortin. Finally, the bound radioactivity (due to Cortisol-H3) is measured which is then employed to calculate exactly the amount of cortisol present in the sample by the help of a Standard Curve (or Calibration Curve). 

In all applications where finely divided powders are used (such as talcum, cement, charcoal powder), the property of these will depend mainly on the surface area per gram (varying from a few square meters [talcum] to over 1000 m2/g [charcoal]). For example, if one needs to use charcoal to remove some chemical (such as coloring substances) from wastewater, then it is necessary to know the amount of absorbent needed to fulfill the process. In other words, if a 1000 m2 area is needed for adsorption when using charcoal, then 1 g of solid will be required. In fact, under normal conditions, swallowing charcoal would be considered dangerous because it would lead to the removal of essential substances from the stomach lining (such as lipids and proteins). 

Yuan, J., Yang, D.C., Birkmeier, J. and Stolzenbach, J. (1995) Determination of protein binding by in vitro charcoal adsorption. Journal of Pharmacokinetics and Biopharmaceutics, 23, 41-55. 

Biotin is present in natnre predominantly bonded to protein and is relatively stable therefore it can be extracted under hard conditions, snch as autoclaving in sulfuric acid. Enzyme digestion is also applied to break the protein-biotin bond. A following purification is usually performed by adsorption on charcoal or by lEC. 

Endogenous biotin in foods is predominately protein bound and is relatively stable (180). Consequently it can be extracted under fairly harsh conditions, e.g., autoclaving in 4 M sulfuric acid for 2 hours at 120°C. Enzymatic hydrolysis with papain will also release biotin from proteins (181). Potential sample-cleanup procedures include adsorption on charcoal and/or ion-exchange chromatography (182,183). 

Once lipolysis has occurred there is little that can be done to reduce its effects on quality, although, in laboratory trials, Nakai (1983) successfully removed FFAs from rancid milk by adsorbing them on activated charcoal and Takacs et al. (1989) by the use of a C18 column. However, such nonspecific adsorption methods are unlikely to find widespread use as other milk components such as proteins and vitamins are also removed. 

This appears to be the case for albumin, probably because of the fatty acid content of this protein. Markedly different adsorption isotherms were observed for different albumin preparations, and some isotherms did not appear to reach a plateau adsorption level even at physiological albumin concentrations see upper curve in Figure 5). Removal of the fatty acid by the acid charcoal method of Chen (31) appears to normalize the appearance of the isotherm see the lower curve in Figure 5). Since the fatty acid content of various albumin preparations varies markedly, the variations in apparent adsorption behavior of different albumin preparations appears to be attributable to this cause see Table III). 

A protein binding assay for cyclic AMP using rabbit skeletal muscle has been described [151]. A similar method uses a binding protein from bovine adrenal cortex whose preparation is simple and can be accomplished in 2-3 hr [152-154]. The preparation can be stored at -20°C for at least 3 months. Unbound cyclic AMP is separated from bound cyclic AMP by adsorption on charcoal and as little as 0.01 pmol of cyclic AMP per tube can be identified. 

A second type of nonessential water is called sorbed water and is encountered with many colloidal substances, such as starch, protein, charcoal, zeolite minerals, and silica gel. In contrast to adsorption, the quantity of sorbed water is often large, amounting to as much as 20% or more of the total mass of the solid. Solids containing even this amount of water may appear to be perfectly dry powders. Sorbed water is held as a condensed phase in the interstices or capillaries of the colloidal solid. The quantity contained in the solid is greatly dependent on temperature and humidity. 

The acridine dye, Rivanol (2-ethoxy-6 9-diaminoacridine lactate), has been shown to be useful for the preparation of y-globulins. A 0.4 per cent solution of the dye added to plasma at pH 7.6-7.8 will precipitate all the plasma proteins except the y-globulins. The excess dye can then be removed by adsorption on Norit charcoal, and the y-globulins recovered by precipitation with 25 per cent ethanol at -5°C. 

Passage of blood through a column of charcoal or adsorbent resin (hemoperfusion) is a technique for the extracorporeal removal of a poison. Because of the high adsorptive capacity and affinity of the material in the column, some chemicals that are bound to plasma proteins can be removed. The principal side effect of hemoperfusion is depletion of platelets. 

For the preliminary separation of a complex protein hydrolyzate into simpler peptide mixtures, ionophoretic methods are probably the most generally useful. Aromatic peptides may be separated by adsorption on charcoal and cystine peptides by oxidation. 

In the presence of CH2-H4folate, FdUMP forms a specific, stable complex with thymidylate synthetase in which all components are covalently bound as depicted in Fig. 1. The affinity constant of this complex is suflSciently high that, with typical concentrations of components used in most experiments, the limiting reagent (FdUMP or enzyme) is completely bound. Using [ H]FdUMP of high specific activity, low levels of complexes present in solution may conveniently he assayed by retention on nitrocellulose filter membranes under conditions in which the free nucleotide is readily removed. The radioactivity remaining on the filter is determined to quantitate the complex. Other conventional methods (e.g., gel filtration, charcoal adsorption of free FdUMP, protein precipitation) may be used for this purpose, but are more tedious and apparently less eflicient. There are expectedly few proteins that will form isolable... 

In protective clothing, a layer of polyurethane, foam-entrapped, activated charcoal is embedded between several layers of polyester fabric. Polyurethanes are effective substrates for OP adsorption, and reports have documented that polyurethane foam particles can be used as adsorbent materials for pesticide vapors in farming fields. If proteins could be incorporated into polyurethanes, some interesting materials might emerge. 

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