Serum albumin solubility

Bovine serum albumin Solubility enhancer (for biomolecules)... 

Masuelli M. A. 2013. Study of bovine serum albumin solubility in aqueous solutions by intrinsic viscosity measurements. Ady hy Chem., 2013, Article ID 360239, 8 pages. 

The qualitative thermodynamic explanation of the shielding effect produced by the bound neutral water-soluble polymers was summarized by Andrade et al. [2] who studied the interaction of blood with polyethylene oxide (PEO) attached to the surfaces of solids. According to their concept, one possible component of the passivity may be the low interfacial free energy (ysl) of water-soluble polymers and their gels. As estimated by Matsunaga and Ikada [3], it is 3.7 and 3.1 mJ/m2 for cellulose and polyvinylalcohol whereas 52.6 and 41.9 mJ/m2 for polyethylene and Nylon 11, respectively. Ikada et al. [4] also found that adsorption of serum albumin increases dramatically with the increase of interfacial free energy of the polymer contacting the protein solution. 

Aqueous solubility is not usually considered a priori as a problem in the drug discovery of acidic compounds. More important issues are (i) the high serum albumin binding of stronger acids, (ii) the very low or nonexistent central nervous system penetration of stronger acids, (iii) the low volumes of distribution of acids limiting these mostly to plasma compartment targets, (iv) the possibility of formation of... 

Many extracellular proteins like immunoglobulins, protein hormones, serum albumin, pepsin, trypsin, ribonuclease, and others contain one or more indigenous disulfide bonds. For functional and structural studies of proteins, it is often necessary to cleave these disulfide bridges. Disulfide bonds in proteins are commonly reduced with small, soluble mercaptans, such as DTT, TCEP, 2-mercaptoethanol, thioglycolic acid, cysteine, etc. High concentrations of mercaptans (molar excess of 20- to 1,000-fold) are usually required to drive the reduction to completion. 

The F/P ratio of the purified, labeled protein may be determined by measuring the absorbance at 345 and 280nm. Ratios between 0.3 and 0.8 usually produce labeled molecules having acceptable levels of fluorescent intensity and good retention of protein activity. AMCA-labeled proteins may be lyophilized without significant loss of fluorescence. The addition of bovine serum albumin (15mg/ml) or another such stabilizer is often necessary to retain solubility of the freeze-dried, labeled protein after reconstitution. 

It is important, however, to remove the protein layer from the surface over which the air/liquid meniscus is displaced during the measurement so as to assure that the conditions of flow with and without the layer in the capillary are totally comparable. Using this method we find that in the case of bovine serum albumin very thick layers are formed layers whose thickness grows in direct proportionality to albumin concentration up to 15% w/v, at least. We also find a reversible doubling of layer size as temperature is raised from 7.7 to 15°C in the case of triple helical soluble collagen adsorbed end on to glass. 

Fig. 8.7 CTB-GM1-ganglioside binding ELISA assay. Plates, coated first with GMrganglioside and bovine serum albumin (BSA), respectively, were irrigated with total soluble plant protein from chloroplast transgenic lines (3 and 7) and 300 ng of purified bacterial CTB. The absorbance of the GM1-ganglioside-CTB-antibody complex in each case was measured at 405 nm. Total soluble protein from untransformed plants was used as the negative control.

Bilirubin is not water soluble and is therefore transported in the blood attached to serum albumin. 

High temperatures can break native S-S bonds and form new S-S bonds which can lock the protein into a denatured eonfiguration [89]. Low pH, sodium dodecyl sulfate. Tween 80, chaotropie salts, and exogenous proteins have been used to protect proteins from thermal inaetivation [90]. Ethylene glycol at 30-50% was used to protect the antiviral activity of P-interferon preparations [91]. Human serum albumin was used in recombinant human interferon-Psei-n which resulted in increased thermal stability [62]. Water-soluble polysaeeharides sueh as dextrans and amylose [92], as well as point-specific (site-directed) mutagenesis [93] have also been used to increase thermal stability of therapeutie proteins and peptides. 

Proteins are water-soluble biopolymers with a huge number of potential donor atoms and coordination sites which could make them useful carriers of metal complex catalysts. Indeed, a few successful attempts can be found in the literature [139] but often the interaction of proteins and metal complexes lead to a loss of catalytic activity [140]. This was not the case with human serum albumin (HSA) which formed a stable and active catalytically active complex with [Rh(acac)(CO)2]. In the hydroformylation of 1-octene and styrene the selectivity towards aldehydes was excellent, moreover styrene reacted with high regioselectivity (b/1 = 19). The activity... 

Ab, Antibody BBB, Blood Brain Barrier CNS, Central Nervous System HIV, Human Immunodeficiency Virus HSA, Human Serum Albumin IGF, Insulin Growth Factor I/R, Ischaemia/Reperfusion MW, Molecular Weight OxLDL, Oxidized Low Density Lipoprotein -R, -receptor sCD4, soluble CD4 VEGF, Vascular Endothelial Growth Factor. 

Most frequently, binding protein is added to the incubation mixtures as either serum or purified serum albumin. With human serum albumin, at equilibrium, the acceptor substrate will largely be protein-bound, when the bilirubin albumin molecular ratio is smaller than one (the dissociation constant of the first binding site of purified human serum albumin is approximately 7 X 10 M with 2 X 10 M for two additional binding sites) (J2). The first binding site of albumin, measured with rat serum, has a dissociation constant of about 5 X 10" M (M8). The unbound fraction will normally not exceed the very low solubility of the pigment. Addition of albumin to an alkaline solution of bilirubin, or its addition immediately after neutralization, prevents colloid formation, if the bilirubin albumin molecular ratio is smaller than one (B25). However, colloidal bilirubin, once formed, cannot be redissolved by the addition of albumin (B26). 

Chemical reactions Polymerization of casein and whey proteins are due to some kind of chemical reactions. The different proteins as found in the supernatant of milk after precipitation at pH 4.6 are collectively called whey proteins. These globular proteins are more water soluble than caseins and are subject to heat dena-turation. Denaturation increases their water-binding capacity. The principal fractions are P-lactoglobulin, a-lactalbumin, bovine serum albumin (BSA), and immunoglobulins (Ig). 

The apparent permeability of 11 test compounds was measured in the presence and absence of human serum albumin in the donor compartment, and by solving the differential equations describing the kinetics of membrane permeability, membrane retention and protein binding, the authors were able to obtain the Kd. With the protein in solution rather than immobilized and without the need for mass balance or equilibrium conditions, this approach provides an attractive alternative to existing methods with the potential to be applied to an array of other soluble proteins. 

Human serum albumin Potato 0.02% of soluble leaf protein... 

Decreased serum albumin elimination half-lives of fat-soluble drugs... 

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