Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Physicochemical properties of the matrix proteins of three main culture vehicles (1994)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 44 (1994), S. 29-37 
    Details
    ISSN: 0006-3592
    Keywords: proteins, contaminant ; Escherichia coli ; Saccharomyces cerevisiae ; mammalian cell culture ; PAGE ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The protein components of three industrial recombinant expression systems: Escherichia coli, Saccharomyces cerevisiae, and a mammalian cell culture supernatant of CHO cells were characterized in terms of their molecular weight, isoelectric point, and relative surface hydrophobicity. Identification of individual proteins was done by reference to their position in protein band profiles by polyacrylamide gel electrophoresis (PAGE) of the crude material. This permitted a rapid and facile assignment of quantitative values for these three parameters to all the major protein components in these materials. Because it is the indigenous proteins in expression systems that will form the bulk of any impurities in the product, once the values of these parameters are known for any target recombinant protein, the data obtained will enable appropriate expression systems to be chosen for minimizing amounts of potential contaminants and reducing downstream processing requirements and costs. The data will also indicate which fractionation steps (i.e., charge, size or hydrophobicity-based) are likely to be best for distinguishing between target and contaminant proteins, thus aiding and early removal of the maximum quantities of undesired protein to bring subsequent bioseparation steps down in scale and cost and up in terms of efficiency. © 1994 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260440106
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Use of chemically modified proteins to study the effect of a single protein property on partitioning in aqueous two-phase systems: Effect of surface charge (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 49 (1996), S. 309-315 
    Details
    ISSN: 0006-3592
    Keywords: surface charge ; proteins, modified ; partitioning in aqueous system ; thaumatin ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A series of charge-modified thaumatins with different values of surface charge were partitioned in aqueous two-phase systems (ATPS) to study the effect of surface charge as a single property on partitioning. Electrophoretic mobility of the proteins in titration curves was used as a measure of surface charge. Four modified proteins derived from thaumatin with the following values of isoelectric point: 8.70, 8.15, 5.60, and 4.50 were used for partitioning. The resolution of the systems in terms of protein surface charge was calculated. Partitioning of modified thaumatins in PEG 4000/dextran systems with phosphate buffer, Tris buffer, NaCl, KCl, and sulfate salts was carried out. Among the sulfate salts tested, the addition of 50 mM Li2SO4 to the system buffered with phosphate gave the highest value of resolution for differences in surface protein charge (RSPC). It shows a decrease in the value of K (partition coefficient) with an increase in the protein's charge. The addition of 100 mM KCl to the system promoted the opposite effect on the RSPC value. Charge-modified proteins were partitioned in PEG/salt systems to investigate the ability of these systems for resolving differences in surface charge. The PEG/citrate system seemed to have almost no ability for resolving proteins on the basis of surface charge differences; PEG/phosphate systems had some capability for resolving differently charged proteins. The more negative proteins tended to have higher values of K than the more positively charged fractions. The use of charge-modified proteins allowed the investigation of the effect of protein surface charge on partitioning in aqueous two-phase systems independently from other protein parameters as they were prepared from a common parent protein thaumatin. This technique provides an interesting novel tool to investigate the effect of protein surface charge on partitioning in ATPS taking protein charge as an independent parameter. © 1996 John Wiley & Sons, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Conservative chemical modification of proteins to study the effects of a single protein property on partitioning in aqueous two-phase systems (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 49 (1996), S. 290-299 
    Details
    ISSN: 0006-3592
    Keywords: proteins, modified ; partitioning in aqueous system ; thaumatin ; β-lactoglobulin ; BSA ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Relatively conservative modifications of three proteins were carried out to alter their surface properties. The protein properties modified were hydrophobicity and charge. This was done by acylation of amino groups with anhydrides. For the hydrophobic modification experiments, two proteins (β-lactoglobulin and bovine serum albumin [BSA]) and four anhydrides (hexanoic, butyric, succinic, acetic) were used. For the modification of surface charge the protein thaumatin was selected and various proportions of the free amino groups were blocked with acetic anhydride to give a series of proteins with differing isoelectric points. Detailed characterization and purification of selected modified proteins was carried out including molecular weight measurements and conformational analysis. The criteria used for selecting the modified proteins for subsequent investigation of their partitioning in aqueous two-phase systems (ATPS) is described. With a judicious choice of starting material it was found that limited chemical modifications to proteins could effectively alter surface hydrophobicity or charge almost independently, with little effect on other molecular properties. It appears, however, that the method for chemical modification and the reaction conditions must also be carefully controlled. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Use of chemically modified proteins to study the effect of a single protein property on partitioning in aqueous two-phase systems: Effect of surface hydrophobicity (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 49 (1996), S. 300-308 
    Details
    ISSN: 0006-3592
    Keywords: hydrophobicity ; proteins, modified ; partitioning in aqueous system ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Two different series of hydrophobically modified proteins were partitioned in a number of aqueous two-phase systems (ATPS) to investigate the effect of hydrophobicity as a single property on partitioning. The modified proteins were derived from β-lactoglobulin and bovine serum albumin (BSA). Measurement of the surface hydrophobicity of the proteins is important; hydrophobic interaction chromatography (HIC) was used for this purpose. The resolution of the systems (R) in terms of protein surface hydrophobicity and the intrinsic hydrophobicity (log P0) of the systems was established. The effect of the addition of NaCl to PEG/phosphate and PEG/dextran systems was analyzed in terms of the hydrophobicity difference between the phases and their ability to promote hydrophobic interactions between the protein surface and the PEG molecules. The values for R and log P0 differed somewhat depending on which group of modified proteins was used for partitioning. The addition of NaCl to PEG/phosphate systems promoted an increase in the values of R, showing an important effect on the resolution of the systems for protein surface hydrophobicity (twice as high when compared with systems without NaCl). For PEG/dextran systems, the addition of 9% NaCl (w/w) promoted an improvement in the resolution toward surface hydrophobicity with an increase of 60% on the value of R. © 1996 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...