Wilma Dormeyer

Ruhr-Universität Bochum, Bochum, North Rhine-Westphalia, Germany

Are you Wilma Dormeyer?

Claim your profile

Publications (4)12.27 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Human cerebrospinal fluid is an ultrafiltrate of plasma that is largely produced by the choroid plexus. It consists of a mixture of anorganic salts, various sugars, lipids and proteins from the surrounding brain tissues. The predominant proteins in cerebrospinal fluid are isoforms of serum albumin, transferrin and immunoglobulins, representing more than 70% of the total protein amount. A rough overview of the protein compounds of human cerebrospinal fluid including their respective concentrations is given by Blennow et al. [Eur. Neurol. 33 (1993) 129]. In contrast, the aim of this work is to display the detailed protein composition of CSF by two-dimensional gel electrophoresis and to identify both high and low concentrated proteins using different mass spectrometry techniques. This extensive overview of proteins in human cerebrospinal fluid will be highly relevant for clinical research. Furthermore, the comparison of 2D gels will help to analyze the standard protein variability in CSF of healthy persons and detect specific protein variations of patients with various neurological diseases (e.g., Alzheimer's disease, Huntington's chorea). Sample preparation for two-dimensional gel electrophoresis must include concentration and desalting steps such as precipitation and ultrafiltration due to the high amount of salts, sugars and lipids and the low total amount of protein of 0.3-0.7 microg/microl present in human CSF. Up to now we were able to identify more than 480 spots from suchlike generated 2D gels using MALDI- and ESI-mass spectrometry.
    Journal of Chromatography B 06/2002; 771(1-2):167-96. · 2.49 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A method for the analysis of the rViscumin heterodimer (recombinant mistletoe lectin) based on two-dimensional (2-D) polyacrylamide gel electrophoresis and mass spectrometry was developed and used for quality control concerning purity and homogeneity of the recombinant protein processed under Good Manufacturing Practice (GMP) conditions. A series of spots with different pI-values in the pH-gradient of both rViscumin A- and B-chain were observed independently from the experimental conditions like urea concentration, heat treatment or the use of cysteine alkylating agents. Comparative studies of the major spots using matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS), liquid chromatography-electrospray ionization (LC-ESI)-MS and LC-ESI-tandem MS (MS/MS) after tryptic in-gel digestion resulted in a sequence coverage of 92% for the A-chain and 95% for the B-chain. No molecular differences like common chemical or post-translational modifications or nonenzymatic deamidation were found to cause the different charge values of the separated spots. Therefore, these protein spots were extracted from the 2-D gel and separated again by 2-D gel electrophoresis (termed Re-2-DE). Each of the single spots tested in the Re-2-DE experiment split up in the same heterogeneous pattern concerning the pI-values. We suggest that the observed charge variants of rViscumin are the result of conformational protein variants, existing in an equilibrium during sample preparation and/or isoelectric focusing and are not caused from microheterogeneity in the primary structure of rViscumin.
    Electrophoresis 09/2001; 22(14):2888-97. · 3.26 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A method for the analysis of the rViscumin heterodimer (recombinant mistletoe lectin) based on two-dimensional (2-D) polyacrylamide gel electrophoresis and mass spectrometry was developed and used for quality control concerning purity and homogeneity of the recombinant protein processed under Good Manufacturing Practice (GMP) conditions. A series of spots with different pI-values in the pH-gradient of both rViscumin A- and B-chain were observed independently from the experimental conditions like urea concentration, heat treatment or the use of cysteine alkylating agents. Comparative studies of the major spots using matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS), liquid chromatography-electrospray ionization (LC-ESI)-MS and LC-ESI-tandem MS (MS/MS) after tryptic in-gel digestion resulted in a sequence coverage of 92% for the A-chain and 95% for the B-chain. No molecular differences like common chemical or post-translational modifications or nonenzymatic deamidation were found to cause the different charge values of the separated spots. Therefore, these protein spots were extracted from the 2-D gel and separated again by 2-D gel electrophoresis (termed Re-2-DE). Each of the single spots tested in the Re-2-DE experiment split up in the same heterogeneous pattern concerning the pI-values. We suggest that the observed charge variants of rViscumin are the result of conformational protein variants, existing in an equilibrium during sample preparation and/or isoelectric focusing and are not caused from microheterogeneity in the primary structure of rViscumin.
    Electrophoresis 08/2001; 22(14):2888 - 2897. · 3.26 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this work is to display the protein composition of the cerebrospinal fluid by two-dimensional (2-D) gel electrophoresis and identify it using different mass spectrometric techniques. This will enable us to present an overview of the proteins in human cerebrospinal fluid. The comparison of 2-D gels will help us to analyze the normal protein variability in healthy persons and specific protein variations in patients with different neurological diseases (e.g., morbus Alzheimer, chorea Huntington). However, it is not possible to carry out 2-D gel electrophoresis directly with human cerebrospinal fluid due to the high amount of salts, sugars and lipids present. In addition, the total amount of protein is only as high as 0.3-0.7 microg/microL. Therefore, concentration and desalting steps using precipitation and ultrafiltration are necessary. To date we have been able to identify more than 65 spots from 2-D gels using matrix assisted laser desorption/ionization-mass spectrometry and electrospray ionization-mass spectrometry.
    Electrophoresis 08/2000; 21(13):2721-8. · 3.26 Impact Factor

Publication Stats

122 Citations
12.27 Total Impact Points

Institutions

  • 2001
    • Ruhr-Universität Bochum
      • Institut für Physiologische Chemie
      Bochum, North Rhine-Westphalia, Germany