Serum albumin, bovine passaging

The reaction mixture for /3-galactosidase contained in a final volume of 0.5 mL 50 mM sodium citrate buffer (pH 3.5), 0.1 U/mL of /3-galactosidase, 1 mg/mL of bovine serum albumin, 0.02% sodium azide, 1 mM a-L-fucose (internal standard), and lactose (5-40 mM). The assay was conducted at 30°C. Aliquots of 20 fiL were removed at 8-minute intervals up to 48 minutes and added to 1 mL of distilled water at 4°C. The hydrolysis of substrate did not exceed 5%. Samples were desalted by passage through a column containing 0.2 mL each of Dowex AG50W-X12 (H+ form) and Dowex AG3-X4 (OH-form). The column was washed with 2 mL of distilled water and the eluate evaporated to dryness and taken up in water to give a lactose concentration of 0.2 mM. A 175 fiL aliquot was used for HPLC analysis. 

To our knowledge the first appheation of ODMR to a molecule of biological importance was made by Kwiram who in 1970 reported the optical detection of magnetic resonance signals from the tryptophan moiety of lysozyme. A more recent report dealt with frozen glassy solutions of tryptophan, tyrosine, and the protein, bovine serum albumin (BSA) loob) See Fig. 10. Discrepancies between the lifetimes involved in the phosphorescence decay and the fast-passage ODMR responses... 

A study by Jiang et al. in which PCL was used as the sheath and bovine serum albumin (BSA) or lysozyme-doped poly(ethylene glycol) (PEG) as the core showed that the structure and functionality of the released proteins were unaltered. Later work, involving a blend of PCL and PEG in the sheath and BSA or lysozyme-added dextran in the core, showed that the release rate of the proteins encapsulated could be tuned simply by altering the chemical composition of the sheath. The release rate depended on the fraction of PEG which, being soluble in water, formed pores in the sheath and provided a passage for the release of the protein. 

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