Heat stabilization, albumin

V heat stabilized albumin microspheres - 40h at 150 C, tj release in vitro 9.2h suspension... 

Heat stabilized albumin microspheres, 12h at 150 C, t release in vitro = lh... 

Chatteijee, J., Haik, Y, and Chen, C. J. 2001. Synthesis and characterization of heat-stabilized albumin magnetic microspheres. Colloid. Polym. Sci. 279 1073-1081. 

Inactivation and Removal of Viruses. In developing methods of plasma fractionation, the possibiHty of transmitting infection from human vimses present in the starting plasma pool has been recognized (4,5). Consequentiy, studies of product stabiHty encompass investigation of heat treatment of products in both solution (100) and dried (101) states to estabHsh vimcidal procedures that could be appHed to the final product. Salts of fatty acid anions, such as sodium caprylate [1984-06-17, and the acetyl derivative of the amino acid tryptophan, sodium acetyl-tryptophanate [87-32-17, are capable of stabilizing albumin solutions to 60°C for 10 hours (100) this procedure prevents the transmission of viral hepatitis (102,103). The degree of protein stabilization obtained (104) and the safety of the product in clinical practice have been confirmed (105,106). The procedure has also been shown to inactivate the human immunodeficiency vims (HIV) (107). 

HSA is used therapeutically as an aqueous solution it is available in concentrated form (15-25 per cent protein) or as an isotonic solution (4-5 per cent protein). In both cases, in excess of 95 per cent of the protein present is albumin. It can be prepared by fractionation from normal plasma or serum, or purified from placentas. The source material must first be screened for the presence of indicator pathogens. After purification, a suitable stabilizer (often sodium caprylate) is added, but no preservative. The solution is then sterilized by filtration and aseptically filled into final sterile containers. The relative heat stability of HSA allows a measure of subsequent heat treatment, which further reduces the risk of accidental transmission of viable pathogens (particularly viruses). This treatment normally entails heating the product to 60 °C for 10 h. It is then normally incubated at 30-32 °C for a further 14 days and subsequently examined for any signs of microbial growth. 

PPV was also extracted with chloroform, but chloroform extraction had little effect on PPV inactivation during albumin pasteurization (Fig. 7). These results are comparable to previous reports of only l-21ogio Minute Virus of Mice, another parvovirus, inactivation after 6 hr of pasteurization in 1% albu-min.f Thus, heat stability during pasteurization... 

Fig. 2. Effect of KODl CpkB on heat stabilization of ADH. (a) Thermal inactivation of ADH and CpkB- mediated reactivation in vitro. The yeast ADH (0.025 p.M) was incubated for 6 min at temperatures between 30° and 70° in the absence ( ) or presence ( ) of purified recombinant CpkB (0.25 p,M) and remaining ADH activity was assayed. ( ) indicates remaining ADH activity in the presence of bovine serum albumin (0.25 p.M). (b) CpkB dependent stabilization of ADH. The ADH (0.025 p.M) was incubated at 50° either without ( ) or with 0.25 p.Af CpkB ( ) 0.25 iM CpkB and 10 mAf ATP (O) 0.025 xAf CpkB (A) 0.025 pAf CpkB and 10 mAf ATP (A) and 0.25 p,Af bovine serum albumin ( ). ADH activity was measured at the times indicated.

AFJr Yapel. Albumin microspheres heat and chemical stabilization. In KJ Widder, R Green, eds. Methods in Enzymology Part A, Drug and Enzyme Targeting. Orlando Academic Press, 1985, pp 3-18. 

Triton X-100, EDTA, dithiothreitol and electrolyte protect enzyme in dilute solution and against denaturation by heat or extreme pH-values [12, 48] <2>, at low dithioerythritol concentrations enzyme tends to aggregate [5] <2>, bovine serum albumin, 1 mg/ml, stabilizes dilute enzyme solutions [5] <2>, diadenosine pentaphosphate, i.e. AP5A, stabilizes during preparative electrophoresis [7]... 

Bovine serum albumin is denatured at pH 4 because of repulsion of acidic amino acids (Haurowitz 1963). As with a-lactalbumin, failure to measure the heat of denaturation for bovine serum albumin at pH 3 indicates that it is already unfolded by acid (de Wit and Klarenbeek 1984). It is more stable at pH 7.5 than at pH 6 because of increased activity of thiol groups at high pH. Denaturation is enhanced more by calcium ions than by other anions (Shimada and Matsushita 1981). Fatty acids appear to stabilize bovine serum albumin against heat denaturation (Gumpen et al 1979). 

Insulin Insulin may be stable for 1 month if stored at a temperature of 25 °C, but care should be exercised not to expose it to heat or light. However, for better stability, storing at refrigerator temperature (2° to 8 °C) is recommended. Use of carrier proteins such as albumin can be formulated along with insulin preparations, since they adsorb to containers. 

---