Solubility protein

Branden, C., and Tooze, J. (1999). Introduction to Protein Structure, 2nd edition. New York Garland Publishing. 

Davies, J. S., ed. (1985). Amino Acids and Peptides. New York Chapman Hall. 

(2000). Introduction to Protein Architecture The Structural Biology of Proteins. Oxford Oxford University Press. 

and Voet, J. G. (1995). Biochemistry, 2nd edition. New York Wiley. 

At the surfaces of proteins are amino acid residues that interact with water. The amino acids are referred to as hydrophilic amino acids and include arginine, lysine, aspartic acid, and glutamic acid. At pH 7 the side chains of these amino acids carry charges—positive for arginine and lysine, negative 

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Texturization is not measured directly but is inferred from the degree of denaturation or decrease of solubility of proteins. The quantities are determined by the difference in rates of moisture uptake between the native protein and the texturized protein (Kilara, 1984), or by a dyebinding assay (Bradford, 1976). Protein denaturation may be measured by determining changes in heat capacity, but it is more practical to measure the amount of insoluble fractions and differences in solubility after physical treatment (Kilara, 1984). The different rates of water absorption are presumed to relate to the degree of texturization as texturized proteins absorb water at different rates. The insolubility test for denaturation is therefore sometimes used as substitute for direct measurement of texturization. Protein solubility is affected by surface hydrophobicity, which is directly related to the extent of protein-protein interactions, an intrinsic property of the denatured state of the proteins (Damodaran, 1989 Vojdani, 1996). 

Transport in blood Bound to carrier proteins Soluble in plasma Bound to carrier proteins Soluble in plasma... 

Arakawa, T. and Timasheff, S.N. (1985) Theory of protein solubility. Methods in Enzymology 114, 49-77. 

On the other hand, pDNA/PEI polyplexes were found to be not stable enough in the extracellular in vivo environment. Unpackaging of PEI and PEG-PEI polyplexes was observed [64, 65, 81], for example by serum proteins, soluble glycosaminoglycans, or extracellular matrix components. The situation is even worse in the case of siRNA polyplexes, where PEI polyplexes are dissociated in full human serum, as monitored by fluorescence fluctuation spectroscopy [66, 67]. 

C. Tribet, R. Audebert, J.-L. Popot (1996) Amphipols polymers that keep membrane proteins soluble in aqueous solutions. Proc. Natl. Acad. Sci. USA, 93 15047-15050... 

C. Prata, F. Giusti, Y. Gohon, B. Pucci, J.-L. Popot, C. Tribet (2001) Non-ionic amphiphilic polymers derived from Tris(hydroxymethyl)-acrylamidomethane keep membrane proteins soluble and native in the absence of detergent. Biopolymers, 56 77-84... 

When attempting to use NMR to measure a dissociation constant, the basic experiment will be to vary the ligand concentration in the presence of a fixed concentration of protein. (The converse experiment, varying the protein concentration, may sometimes be carried out, but is generally less satisfactory because of problems with protein solubility and aggregation.) What one sees in this experiment will depend critically on the rate of... 

A number of the actions of NO in target cells may be explained by its binding to the haem-containing protein soluble guanylyl cyclase (sGC), an enzyme which generates a second messenger, cyclic GMP (cGMP) from GTP. 

Differential hydration of proteins has been little exploited as a selectivity factor in ion exchange, but it is simple to evaluate and can produce useful results. This technique relies on the preferential exclusion of certain solutes from protein surfaces to produce an exclusionary effect and favor their interaction with the column. Protein hydration is generally proportional to protein size and solubility. Among proteins of similar size, this predicts that retention will increase with protein solubility. Among proteins of similar solubility, retention increases with protein size.16... 

Wigley, W.C., Stidham, R.D., Smith, N.M., Hunt, J.F., and Thomas, P.J., Protein solubility and folding monitored in vivo by structural complementation of a genetic marker protein, Nat. Biotechnol., 19,131, 2001. 

Proteins crystallized from very low salt concentrations (examples are carboxypeptidase A and elastase) can often be treated exacdy like proteins crystallized from alcohol-water mixtures. Their low solubility in water allows them to be transferred from their normal mother liquor to a distilled water solution or to a solution of low (10-20%) alcohol concentration without disorder. It is advisable to carry out this transfer at near 0 C to further decrease the protein solubility. From this stage it is trivial to add alcohol while cooling, as described above. Complications arise, however, when the salt employed as a precipitant in the native mother liquor is insoluble in alcohols. The solution to this problem is to replace the salt by ammonium acetate at equivalent or higher ionic strength. Ammonium acetate is soluble up to 1 M in pure methanol, and is very soluble in nearly all alcohol-water mixtures, even at low temperature. It therefore provides a convenient substitute for salts such as sodium sulfate or sodium phosphate. 

Some 100 different proteins occur in human blood plasma. Based on their behavior during electrophoresis (see below), they are broadly divided into five fractions albumins and ai-, tt2-, P- and y-globulins. Historically, the distinction between the albumins and globulins was based on differences in the proteins solubility -albumins are soluble in pure water, whereas globulins only dissolve in the presence of salts. 

An empirically derived relationships that describes the systematic effects of different neutral salts on the solubility of proteins. Collins and Washabaugh indicate that the order of ionic species eluding from a Sephadex G-10 column corresponds to the known order of effectiveness ions in the Hofmeister series on protein solubility ... 

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