Alcohol precipitation

Processing conditions are closely guarded trade secrets, but manufacturer s Hterature provides some information. The seaweed is extracted with hot water at slightly alkaline pH. The aqueous extract is filtered and recovered by alcohol precipitation, dried, and milled. Dmm-drying provides a less pure product. 

The second assumption was that the maceration released cells Cj and hydrosoluble pectin P. The cell wall of these cells may have been partially degraded to produce non-degradable cells C2 and pectin P]. PI was also partially degraded to ultimate alcohol precipitable pectins P2 and oligouronides O. 

Final alcohol precipitation not only allows for removal of the phenol and any remaining non-covalently bound hydrocarbon but also concentrates the DNA. Ribonuclease treatment removes any contaminating RNA. Additional purification by cesium chloride centrifugation (35) is also often performed. This is particularly suited to small quantities of DNA. Hydroxyapatite chromatography is also effective in separating RNA, proteins, and DNA (36.37). 

Isolate the labeled probe by alcohol precipitation as described previously for nick translation. 

The modified DNA may be recovered by alcohol precipitation according to the method in Section 1 (this chapter) described previously for nick-translation modification. Alternatively, dialysis or gel filtration may be done to remove excess reactants. 

The physical form of the component is extremely important for ease of esterification for amylose, the order of reactivity is amylose complex > freeze-dried or freshly precipitated amylose > alcohol-precipitated, ether-dried amylose, whereas freeze-dried amylopectin is more reactive than... 

In various runs, specific activity went from an average of 2.75 lU/mg protein (based on the Bio-Rad protein assay with bovine serum albumin standard) for Ae centrifuged crude preparation after alcohol precipitation, to 8 lU/mg after DEAE-cellulose chromatography, to 100 lU/mg after DEAE-Fractogel chromatography, to 1000 RJ/mg after Sephadex G-50 chromatography, and to 3200 lU/mg after CM-Trisacryl chromatography. 

The influence of neutral salts as well as of acids and bases on the swelling of gelatine which we have seen can be attributed to an apparent change in the solvation of the gel fibrils and may be interpreted in the light of Donnan s theory of the effect of a non-diffusible ion on the osmotic pressure differences between the two phases, is likewise to be noted in the alteration of the viscosity and alcohol precipitation values of protein solutions. From the considerations already advanced there should exist two well-defined maxima in the viscosity and alcohol precipitation curves when these properties are plotted as functions of the Ph, the maxima coinciding with the points of maximum dissociation of the salts... 

Insulin preparations used initially were little more than crude pancreatic extracts. The therapeutic value of such products was marginal, as severe adverse reactions were commonplace (due to the presence of impurities). This was made worse by the frequency of injections required. The introduction of an acid-alcohol precipitation step yielded insulin preparations of moderate purity, thus partially overcoming the range and severity of side effects noted. 

Complex platinous derivatives containing hydrazine are easily prepared by acting upon dichloro-diammino-platinum with hydrazine hydrate in absence of water. The addition of alcohol precipitates diammino-dihydrazino-platinous chloride in colourless prismatic... 

In 1860, Berthelot56 prepared /3-D-fructofuranosidase from brewer s yeast by alcoholic precipitation. Since then, the /3-D-fructofuranosi-dase activity of yeasts, particularly of Saccharomyces cerevisiae, has been extensively studied, chiefly with sucrose or raffinose as the substrate, because chromogenic /3-D-fructofuranosides have not been available. /3-D-Fructofuranosidases have been reviewed by Neuberg and Mandl,57 Myrback,58 and Lampen59 see also, Ref. 60. 

The final operations of the preparation should be conducted without interruption because aqueous solutions of the complex salt are unstable, especially to light, and deposit insoluble cobalt (II) oxalate on standing. If decomposition of the preparation is suspected, the mother liquor from the alcohol precipitation should be decanted from the product,... 

RNA does not normally precipitate like DNA, but it could still be a minor contaminant. RNA may be degraded during the procedure by treatment with ribonuclease after the first or second deproteinization step. Removal of RNA sometimes makes it possible to denature more protein using chloroform-isoamyl alcohol. If DNA in a highly purified state is required, several deproteinization and alcohol precipitation steps may be carried out. It is estimated that up to 50% of the cellular DNA is isolated by this procedure. The average yield is 1 to 2 mg per gram of wet packed cells. 

Highly purified DNA may be obtained by repeating the chloroform-isoamyl alcohol extraction several times. The alcohol precipitation step may also be carried out many times. Various chromatographic methods including ion exchange have been applied to the purification of nucleic acids. 

In 1911, Hunter described the preparation and properties of silver salts of some halogenated phenols (80). He found that the silver salt of 2.4.6-tribromophenol reacted with ethyl iodide to give a deep blue solution which gradually faded to a brownish yellow. There remained a precipitate of silver bromide and a solution which when added to alcohol precipitated an amorphous product. 

Re cry st alii sation of the foregoing green solid from absolute alcohol gives the telluridichloride as primrose-yellow crystals, almost insoluble in benzene, chloroform, carbon tetrachloride or ethyl acetate, slightly soluble in acetone and readily soluble in hot absolute alcohol. Boiling with 95 per cent, alcohol precipitates tellurium dioxide and the tellurium dichloride passes into solution, but on boiling with 90 per cent, alcohol more than 90 per cent, of unchanged dichloride is recovered. When a hot aqueous sodium carbonate solution of the dichloride is acidified with hydrochloric acid the telluronium chloride is precipitated quantitatively. 

Acid-soluble nucleotides Acid-alcohol precipitant Perchloric acid Uranyl-acetate-trichloracetic acid Uranyl-acetate pH 4 BaC10 + Cellosolve Coprecipitation problems (401) (43) (103) (402) (403, 404) (405)... 

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