Bovine serum albumin release

Bittner, B., Witt, C., Mader, K., and Kissel, T. (1999), Degradation and protein release properties of microspheres prepared from biodegradable poly(lactide-co-glycolide) and ABA triblock copolymers Influence of buffer media on polymer erosion and bovine serum albumin release, J. Controlled Release, 60, 297-309. 

The formation of salt bridges in polyelectrolyte/protein complexes is widely accepted. Direct evidences for the release of counterions upon association of the macromolecular partners are however scarcely reported. Potentio-metric studies were found to reveal the ionization or neutralization of proteins in polymer complexes, i.e., a pKa shift of ionizable residues when an association took place [23,25,30], In the presence of neutral polyethylene glycol, pepsin was shown to take up protons from the solution [30], On the contrary, bovine serum albumin released protons from the addition of poly(diallyldimethylammonium chloride) (Figure 5). Despite the simplicity of both the method and the quantitative measurement of a number of ions released per protein, an interpretation in terms of a number of local bridges... 

He, M.Y., Chu, C.C., 2013. Dual stimuli responsive glycidyl methacrylate chitosan-quatemary ammonium hybrid hydrogel and its bovine serum albumin release. J. Appl. Polym. Sci. 

While the major application of albumin microspheres is in the area of chemotherapy, there have been studies reporting the release of such varied compounds as 1-norgestrel (97), insulin (98), and hematoporphyrins (99) from bovine serum albumin, and the antibacterial sulfadiazine from ovalbumin (100). In general, burst phenomena are found for all systems studied. However, the results from the insulin study are worthy of note in that blood glucose levels were depressed for more than 14 days following the administration of insulin-containing BSA microspheres to diabetic rats. The smaller microspheres were absorbed by day 28 and the larger particles by day 56. 

Proteins may be covalently attached to the latex particle by a reaction of the chloromethyl group with a-amino groups of lysine residues. We studied this process (17) using bovine serum albumin as a model protein - the reaction is of considerable interest because latex-bound antigens or antibodies may be used for highly sensitive immunoassays. The temperature dependence of the rate of protein attachment to the latex particle was unusually small - this rate increased only by 27% when the temperature was raised from 25°C to 35°C. This suggests that non-covalent protein adsorption on the polymer is rate determining. On the other hand. the rate of chloride release increases in this temperature interval by a factor of 17 and while the protein is bound to the latex particle by only 2 bonds at 25°C, 22 bonds are formed at 35°C. 

Jiang and Zhu (2000) and Qiu and Zhu (2001) have reported the fabrication of multilayered devices composed of stacks of compression-molded disks of alternating compositions. One type of disk is either P(SA-EG) or P[SA-co-TMAgly)-Z>-EG] and the other is a pH-sensitive, protein-loaded blend of, for example, poly(methacrylic acid) and polyethoxazoline. The release of model proteins, myoglobin, bovine serum albumin, and FITC-dextran, and compounds such as brilliant blue have been studied and pulsatile release profiles have been demonstrated (Jiang and Zhu, 2000 Qiu and Zhu, 2001). 

Figure 4.7. Histamine release from mast cells in response to various dilutions of HRA generated from bovine serum albumin (BSA) by medium derived from stimulated rat neutrophils [156]. Neutrophils ((50-100) x K lml) were stimulated with FMLP (10 5 M), the medium removed and incubated with BSA (10 mg I ml) at pH 4.5 for 18 h at 37° C. It was then boiled and centrifuged (11,000 x g for 30 s), the supernatant fraction was removed, its pH was adjusted to 7.2 and it was added, at various dilutions, to suspensions of mast cells. Histamine release was then measured after 10 min. As the amount of generated HRA was increased histamine release increased to a maximum at 57 4%. Mean + S.E.M., n = 5. Inset Time-course of generation of HRA as assayed by histamine release from isolated mast cells. HRA was generated as before using 50 x 106 neutrophils/ml. Aliquots were removed at the indicated times and assayed (at 50% dilution) for HRA. Note that there is a significant generation of HRA by 2 h. Mean S.E.M., n = 3.

HLDH) to the ketone 13, from whieh the fluorescent final product umbelliferone (14) is released in each case by the catalytic action of bovine serum albumin (BSA). Thus, by measurement of the fluorescence of 14 for the (J )- and the (5)-substrate separately, the relative amounts of (R)- and (5)-12 can be determined. 

Zhang, F., Guo, J., Peng, X., Fi, Y. (2004) Preparation and release behaviour of carboxy-methylated chitosan/alginate microspheres encapsulating bovine serum albumin. Journal of Applied Polymer Science, 92, 878-882. 

Korchak and Weissmann employed triphenylethylphosphonium as a means of exploring the effects of external sodium on the responses of PMNs to stimulation with an antigen-antibody complex (bovine serum albumin-antibovine serum albumin), an ionophore for calcium (A 23187), and Con A. Both the formation of O by PMNs and the release of their lysosomal enzymes were diminished by reduction in... 

Ogawara, K., Nishikawa, M., Takakura, Y. and Hashida, M. (1998) Pharmacokinetic analysis of hepatic uptake of galactosylated bovine serum albumin in a perfused rat liver. J. Control Release, 50, 309-317. 

LUTEINIZING HORMONE-RELEASING HORMONE conjugated to BOVINE SERUM ALBUMIN... 

Xylanase was assayed using birchwood xylan as substrate. The solution of xylan and the enzyme at appropriated dilution were incubated at 75°C for 3 min, and the reducing sugar was determined by the dinitrosali-cylic acid procedure (12) with xylose as standard. The released color development was measured spectrophotometrically at 540 nm. One unit of enzyme activity was defined as 1 pmol of reducing sugar released 1 min under the described assay conditions. Protein concentration was measured by the Lowry method (13) using bovine serum albumin as standard. 

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