Fetuin

Cell Culture-Derived Media-Derived Protein Impurities. Immunoassays can detect low impurity levels (<1 ppm).4 The ELISA is probably one of the most sensitive analytical methods. If bovine serum is used as a media component, then testing should include ELISAs for bovine serum albumin (BSA), bovine transferrin, bovine fetuin, and bovine IgG. Often hormones and growth factors, such as insulin or insulinlike growth factor, are used as media components. ELISAs should be used to detect and quantitate these residuals in the various production steps as well as in the final product. There are commercially available antibodies to most commonly used media components. If proprietary media components are used, then the same investment in time and effort is required for the production of specific antibodies, as described above for host cell impurities. 

Neeser and Schweizer introduced 4 M CF3CO2H for 1 h at 121° for hydrolysis of glycoproteins. Both neutral and amino sugars were considered. They compared this method to hydrolysis with 0.6 M hydrochloric acid for 4 h at 100° and 3 M hydrochloric acid for 0.75 h at 125°. Hydrolysis of fetal-calf-serum fetuin, bovine submaxillary mucin, and horse-radish peroxidase showed hydrolysis with CF3CO2H to be superior. 

As mentioned in Section 11.2, a special class of proteinaceous targeting constructs are those in which a therapeutic protein is used as the active drug substance. In such a preparation, the protein is redirected to the target tissue by the attachment of site-directing ligands such as those discussed in Section 11.3. For instance, interferon beta (IFN- 3) can be redirected to the liver by enz5matic desialylation in a procedure similar to that described earlier for fetuin (Section 11.3.1). The resultant asialo-IFN- 3 was found to have an in vivo anti-viral effect when tested in a hepatitis B model in athymic nude mice [54]. 

The coupling yield is about 60%. If necessary, check the binding capacity by adsorption of fetuin and elution with 0.1 M N-acetyl-glucosamine in PBS. 

D-Galactose tends to be the next innermost sugar in nonreducing, terminal positions. Thus, about 70-80% of the D-galactose residues of sialic acid-free fetuin,248,319 or of a glycopeptide isolated from it,248 were released by the action of /3-D-galactosidase. Similar results were... 

Bayard investigated a number of glycoproteins (aracid glycoprotein, fetuin, lactotransferrin, transferrin, and ovomucoid) by N-deacetylation followed by deamination.176 They all gave the oligosaccharides 108 and 109, demonstrating the presence of common structural elements in these compounds. 

Bovine serum albumin Transferrin Lactoperoxidase Fetuin-... 

Fetuin -use m cell cultures [CELL CULTURE TECHNOLOGY] (Vol 5)... 

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