Buffers solubilization

Chelants have been employed in cooling water treatments for many years because of their ability to control calcium, magnesium, iron, etc. Formula-tors have also long used chelants because of buffering, solubilization, and oxidation/reduction control effects. 

Sulfonating buffer Solubilization buffer containing Na2S03 at 17 mg/mL and Na2S406 at 5.3 mg/mL. ... 

Sodium carbonate, anhydrous Buffer, solubilizing agent iv, im, ic... 

Dilute the sample 1 10 in the solubilization buffer. Solubilization buffer should be used as the diluent to avoid precipitation of the protein. Determine the protein concentration using the BCA protein assay reagent (or equivalent) according to the manufacturer s instructions. Be sure to include the same amount of the solubilization buffer in the standards because the buffer does affect the color reaction. When adding the solubilization buffer either alone or containing the recombinant protein, it is necessary to mix thoroughly and to work quickly. 

Semipermanent hair color products are formulated at an alkaline pH, usually between 8.5 and 10. At this pH the cuticle of the hair lifts away from the hair a Httie, allowing for easier penetration of dye. An alkyl amine buffered with an organic acid normally is used to obtain the desired pH. The formulations contain a mixture of solvents and surfactants to solubilize the dyes and a thickening agent is added so that the product stays on the hair without mnning or dripping. A 20—30 min appHcation time is normal for this type of product. A representative formula for a semipermanent dye product is given in Table 7. 

For deliming, ammonium salts and acids are used. The proportion of ammonium salts to acids and the type of acids employed is a matter of the tanner s choice. The acid neutralizes the lime, Ca(OH)2, thereby adjusting the pH. The ammonium salts have two functions to buffer the solution to a pH required for bating, and to form calcium ammonium complexes. The acidity and the complex formation solubilize the calcium and serve to bring the hide to the desired pH. 

Concentration Control. Sequestration, solubilization, and buffering depend on the concentration control feature of chelation. Traces of metal ions are almost universally present in Hquid systems, often arising from the materials of the handling equipment if not introduced by the process materials. Despite very low concentrations, some trace metals produce undesirable effects such as coloration or instabiHty. 

Developing agents must also be soluble in the aqueous alkaline processing solutions. Typically such solutions are maintained at about pH 10 by the presence of a carbonate buffer. Other buffers used include borate and, less frequendy, phosphate. Developer solubiUty can be enhanced by the presence of hydroxyl or sulfonamide groups, usually in the A/-alkyl substituent. The solubilization also serves to reduce developer allergenicity by reducing partitioning into the lipophilic phase of the skin (46). 

Fig. 10.4.3 Left panel Bioluminescence spectrum of the acorn worm Ptychodera flava stimulated with H2O2. Right panel (a) The spectrum of the chemiluminescence emitted when 70% dioxane containing 1.7% H2C>2 (5 ml) was added to a mixture of a solution of 2,3,5,6-tetrabromohydroquinone (TBHQ) in ethyl acetate (2.5 ml), 50 mM glycine buffer (pH 12.0 2.5 ml), and riboflavin (b) when riboflavin was omitted and (c) when TBHQ was omitted. Dioxane was included to solubilize the ethyl acetate solution containing TBHQ. From Kanakubo et al., 2005, with permission from Elsevier.

The substances involved in bioluminescence reactions are usually unstable. Thus, the extraction and purification of bioluminescent substances should be carried out in the shortest possible period of time, usually at a low temperature. It is known through experience that luminescent substances are almost always more stable in the original animal tissues than in extracts when preserved at a low temperature. Therefore, before starting extraction and purification, the stability of the extracts and purified substances should be investigated by carrying out a small-scale pilot experiment. A pilot experiment is also essential in the course of purification to avoid an unexpected loss of the target substance. If a component of the luminescence system is insoluble in common buffer solutions, it must be solubilized to purify it (see C1.3). 

In order to solubilize the bound luciferase, the pellet is homogenized with 20-30 volumes of cold 10 mM Tris-HCl buffer, pH 7.5, containing 1M NaCl, and the activity of the homogenate is measured. The homogenate is centrifuged and the activity of supernatant is also measured. A close agreement between the two measurements indicates that 1 M NaCl has solubilized the bound luciferase. If the two values differ significantly, a further effort of solubilization is needed (see Section C1.3). 

Apart from the primary purposes of tying up alkaline earth metals to reduce waterside fouling and solubilizing old, formed deposits, formu-lators have also long used chelants because of their buffering, product stability, and oxidation-reduction control effects. 

The GMT in human serum reacts most rapidly with Y-glutamyl-p-nitroanilide at pH 8.2. The same activity is found in 2-amino-2-methylpropane-l 3 diol, diethanolamine, triethanolamine and tris buffers. Magnesium ions have no effect on the activity but favor the solubilization of the substrate. Bondar and Moss (54) found that free glutamate, due to elevated serum glutamate concentrations or glutamate released by substrate breakdown, increases the apparent GMT activity. They concluded that the assay should be performed in the presence of 1.0 vM/1 glutamate in order to reduce the possibility of falsely elevated results. This was not observed by others. Rowe and co-workers have indicated that certain batches of p-nitroanilide substrate contain impurities which may reduce GMT activity and increase the values ( ). Huesby and Stromme (56) confirmed the presence of such impurities and recommended pyridine extraction for substrate purification. 

Soy cell wall material (Soy CWM) was isolated by Alcalase treatment and jet cooking (115°C, 4 minutes) of soy meal followed by centrifugation and recovery of insolubles. Aliqots of 1% suspensions of soy CWM in O.IM acetate buffer pH 5.0 were incubated with enzymes (40pg of each to 1.5 ml of substrate) at 30°C for 24 hours and the solubilized material was analyzed by HPSEC and HPAEC. 

A detailed descriphon of octanol-water distribuhon coefficient measurements by shake-flask can be found in publications by Dearden [2] and Hansch [24], The method usually involves the following solubilization of the compound in a mixture of mutually presaturated buffered water and octanol, agitation unhl equilibrium has been reached, careful separation of octanol and aqueous phases, and direct measurement of the solute concentration in both phases. Although seemingly simple, the method has a number of caveats making it inappropriate for some compounds. 

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