PubMed Health⌕ Search

Biomedical subjects

B U Sundqvist

Publications and source records attributed to B U Sundqvist.

4 recordsLinked to original sources
PubMed1995

Imaging of single antigens, antibodies, and specific immunocomplex formation by scanning force microscopy.

The most sensitive analytical techniques available today for detecting immuno assay complexes are radio or enzyme immuno analytical techniques, by which quantities of 10(7)-10(8) analyte molecules can be detected. With the introduction of scanning force microscopy, a new method for detecting biological processes became available. Here, we examine the feasibility of using scanning force microscopy as a biosensitive tool. We demonstrate that single or multiple rabbit anti-human serum albumin molecules form complexes with preadsorbed single human serum albumin molecules on mica. However, no interaction is observed between human immunoglobulin G molecules and preadsorbed single albumin molecules; only separate antigens and antibodies are observed at random positions on the mica. This shows the ability of scanning force microscopy to act as a biosensor for detection of immunocomplexes, and to act as a very powerful tool to study molecule-surface interactions in general.

Adsorption↗
PubMed1994

Peptide sequencing by partial acid hydrolysis and high resolution plasma desorption mass spectrometry.

A method of deriving peptide sequence information using partial acid hydrolysis in combination with accurate mass measurements and immonium ion analysis provided by high-resolution plasma desorption mass spectrometry has been developed. The technique is very simple in terms of the chemistry and involves a short-time (3-30 min) incubation of the peptide in 1N-6N HCl at 100-110 degrees C with subsequent mass spectrometric analysis. Partial acid hydrolysis is found to produce sequence-specific segments, often ladder-like, although not always a complete set. Two application examples of the method are given: the linear peptide bradykinin and desmopressin, a peptide with an internal S-S bond and a non-amino-acid constituent. The technique has proved to be particularly useful in cases where some a priori information on the peptide structure was already known or where the automated Edman degradation technique might yield erratic results or not work at all.

Amino Acid Sequence↗
PubMed1989

Laser-induced desorption of proteins.

Laser-induced desorption mass spectrometry has been applied to a number of proteins in the mass range 5000-150,000 u. The beam from an excimer-laser-pumped dye-laser at 266 nm has been focused to a spot of about 50 microns in diameter with irradiances in the 10(7) W/cm2 region. A linear time-of-flight mass spectrometer has been used for mass spectrometric measurements, where positive and negative secondary ions of large proteins have been studied. The effect of different experimental parameters on the protein ion-signal intensities are discussed.

Lasers↗