Ammonium Sulfate Saturation Table

Ammonium sulfate is one of the cheapest and smoothest agents for precipitation of proteins. It is suitable for protein concentration as well as for protein fractionation. 

For description of the amount of ammonium sulfate used for precipitation mostly the term % saturation is used, because at a given temperature the concentration of a saturated ammonium sulfate solution is constant. But because the concentration of saturated solution is temperature dependent, the description should also contain data for temperature of saturated ammonium sulfate solution used for precipitation as well as for sample solution. 

Dawson RM, Elliot DC, Elliot WH, Jones KM (1986) Data for biochemical research, 3rd ed. Clarendon Press, Oxford, p 537 

S starting percentage of satimation of ammonium sulfate, F final percentage of satimation  

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Treatment of the culture filtrate with increasing ammonium sulfate amounts showed that the bulk of polygalacturonase activity precipitates between 45 and 85 % ammonium sulfate saturation (Table 1). 

To obtain a sharper separation of cytochrome a and the cytochromes b and c, it was necessary to collect the fraction precipitating between 26 and 33% saturated ammonium sulfate, instead of that precipitating between 25 and 35%. Use was made of an ammonium sulfate saturation table (Table I). The precipitate was further purified by dialysis and differential centrifugation and crystallized from 10% saturated ammonium sulfate in 0.5% Emasol 4130—0.05 M phosphate buffer at pH 7.2, as shown in Fig. 1. Before the first solubilization with Emasol-phosphate (E-P), a sample of the precipitate must be examined to determine its degree of purification. The precipitate can be solubilized with E-P buffer, if the following criteria are satisfied ... 

Jacob et (d. (Jl) used 4-step ammonium sulfate fractionation of hog gastric mucosal extracts, followed by ultracentrifugation, to obtain high-potency intrinsic factor-active materials (Table 5). The intrinsic factor-containing fraction precipitated between 39 and 47% ammonium sulfate saturation was active at a 1-mg level. About 90% sedimented with a constant of 1.78-1.82 S. Other heavier components formed only about... 

From Na-deoxycholate solubilized brain microsomes the fraction that precipitates between 45 and 60 per cent ammonium sulfate saturation was obtained. This fraction contains ATPases that can be activated with Mg2+ or Ca2+ or Mn2+ in the presence of EDTA and ouabaine (Table 4). In the presence of EGTA (ethanedioxy bis (ethyl amine tetra-acetic acid)) but not ouabaine, and Mg2+ the addition... 

The material from beef serum remained in solution (at pH 6.8) in 0.30 saturated (1.25 M) ammonium sulfate solution (Table II) and precipitated when the salt concentration was increased to 0.41 saturation (1.67 M). These findings by Schales, Holden, and Schales (159) were confirmed by Sapir-stein, Reed, and Southard (154). 

The cyanohydrin product was extracted into organic solvent with the addition of saturated ammonium sulfate (2.5 mL) and ethyl acetate (25 mL) while continuing to stir. The organic layer was transferred to another vessel and evaporated under nitrogen, yielding an oil (Table 1). 

Fractionation conditions are expressed as % saturation . Table 8.19 and 8.20 give the amount of sohd ammonium sulfate necessary to get a distinct degree of saturation starting from a certain starting saturation. 

Tables 8.19 (25 °C) and 8.20 (0 °C) show the amount of solid ammonium sulfate needed to bring up a solution with lower content to a higher percentage of saturation.

Table 8.18. Concentration of ammonium sulfate in saturated solutions at different temperatures...

Precipitation methods are popular first steps in purification of proteins because they can be carried out on a large "batch" scale. The amounts of ammonium sulfate used are often expressed as percentage saturation, i.e., as a percentage of the amount required to saturate the solution (4.1 M at 25°). Convenient tables are available12 78 that permit one to weigh out the correct amount of solid ammonium sulfate to give a desired percentage saturation or to go from one... 

The gas is led to a saturator containing a soluhon of 5 to 10% sulfuric acid where the ammonia is absorbed, and crystalline ammonium sulfate is formed. The gas is fed into the saturator through a serrated distributor underneath the surface of the acid liquid. The acid concentration is maintained by the addition of sulfuric acid, and the temperature is kept at 60°C by the reheater and the heat of neutralization. The crystallized ammonium sulfate is removed from the bottom of the saturator by a compressed-air ejector, or a centrifugal pump, and drained on a table, from which the mother liquor is run back into the saturator. 

Finally, the quantity of ammonium sulfate added must be considered. A number of methods have been proposed to express the quantities of salt added. Figure 10-6 depicts an approach based upon the degree of saturation. At 25 C a saturated solution of ammonium sulfate is 4.1 M in ammonium sulfate (767 g of salt/liter of water). The table indicates the amount of ammonium sulfate that must be added per liter of solution, either free of ammonium sulfate or at some initial concentration, to yield any of the final concentrations listed. Concentrations shown are in terms of percent saturation at 25°C. Since the solubility of ammonium sulfate does not decrease significantly as the temperature drops (3.9M at 0°C), these values are useful regardless of the temperature. If saturated solutions of ammonium sulfate are used the amount to be added may be calculated using the equation... 

The table gives the milliliters of saturated ammonium sulfate solution to be added to one liter of solution to produce the desired change in percent saturation. The volume changes on mixing are negligible. The pH of a saturated ammonium sulfate solution is about 5.5. The pH can be adjusted to 7 by adding a few drops of concentrated NH4OH. 

Since all zinc of human erythrocytes is presumably structurally associated with carbonic anhydrase (Keilin and Mann, 1940a Vallee et al., 1949), the identification of this enzyme in subsequent fractionations provided an indirect check on these calculations. The only fraction in the process of purification exhibiting significant carbonic anhydrase activity was precipitated between 0.85 and 0.90 of full saturation with ammonium sulfate (Table IV). 

The total zinc content of this fraction corresponded closely to that calculated to come from erythrocytes on the basis of the data given in Table III. Previous work (Meldrum and Roughton, 1932a Tupper, Watts, and Wor-mall, 1951 Vallee, Hoch, and Hughes, 1954) has demonstrated that carbonic anhydrase is precipitated at high saturation of ammonium sulfate. These data and calculations indicate, therefore, by correlation of measurements of enzyme activity, zinc content, and the known characteristics of the protein, that two distinct and different zinc-containing proteins exist in leukocytes and erythrocytes and can be differentiated. 

Tables exist to tell you how many grams of ammonium sulfate [(NH j SO ] to add to get a certain percent saturation. A good plan would be to take the homogenate and add enough ammonium sulfate to yield a 20% saturated solution. Let the sample sit for 15 minutes on ice and then centrifuge. Separate the supernatant from the precipitate. Assay both for the protein... 

The chemoattractant material in EWW absorbs at 280nm and 230 nm, contains carbohydrate, is ninhydrin-positive, gives positive Bradford and Lowry test for protein and is precipitated by 90% - 100% saturated ammonium sulfate (Halpern et al., 1984). Earthworm wash retains its chemoattractant properties after dialysis through 50,000 molecular weight (MW) cut off tubing, and lyophilization. However, repeated lyophilization, freeze-drying and thawing, do diminish and eventually destroy the chemoattractant in EWW (Table 1). 

Suppose you put 35.8 g of ammonium sulfate into a flask and add 100 g of water at 0°C. After stirring to dissolve as much solute as possible, will you have a saturated or unsaturated solution Explain your answer. See Table 7.2. 

The majority of aromatic nitrilases hydrolyze not only (hetero) aromatic but also aliphatic saturated or unsaturated nitriles (Table 12.2). The ability of some of the enzymes to hydrolyze acrylonitrile has an industrial impact, as it enables the synthesis of acrylic acid (a polymer building block), the elimination of acrylonitrile from wastewaters [73], or the construction of acrylonitrile biosensors [74]. The nitrilase from R. rhodochrous J1 required activation by ammonium sulfate prior to use for the transformation of acrylonitrile. This activation resided in a rearrangement of the enzyme s quaternary structure, resulting in an increase in molecular weight from... 

Purified according to the method of Okimuki et al. (I9S8) till fraction. Precipitate formed between 26 and 33 o saturated ammonium sulfate (A.S.), instead of between 25 and collected, c.f. Table I and the text. 

Quite recently, a new asymmetric addition reaction has been described by Tiecco. The oxidation of the diselenide 26 with ammonium persulfate produces the camphorselenyl sulfate, which reacts with alkenes in acetonitrile in the presence of water, to afford the hydroxyselenenylation products in good yields and with moderate to good diasteroselectivities [46b]. The results of these experiments are collected in Table 3. Moderate diastereomeric ratios were observed in the hydroxyselenenylation of cyclohexene, styrene and -methylstyrene. Good facial selectivity was observed in all the other cases. The two diastereomeric addition products thus obtained could be separated in most cases. Enantiomerically pure saturated or allylic alcohols... 

TABLE 19.2. Average Electrokinetic Transport Parameters for Sulfate, Nitrate, Phosphate, and Ammonium in Sandy Soil Saturated with Demineralized Water... 

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