liu.seSearch for publications in DiVA
Change search
ReferencesLink to record
Permanent link

Direct link
Comparative proteomics of lowdensity lipoprotein from normal weight and obese adults
Linköping University, Department of Molecular and Clinical Medicine.
Manuscript (Other academic)
URN: urn:nbn:se:liu:diva-14354OAI: diva2:23302
Available from: 2007-03-15 Created: 2007-03-15 Last updated: 2010-01-13
In thesis
1. Lipoproteomics: A New Approach to the Identification and Characterization of Proteins in LDL and HDL
Open this publication in new window or tab >>Lipoproteomics: A New Approach to the Identification and Characterization of Proteins in LDL and HDL
2007 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

A proteomic approach was applied to examine the protein composition of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) in humans. LDL and HDL were isolated by density gradient ultracentrifugation, and proteins were separated with twodimensional gel electrophoresis (2-DE) and identified with peptide mass fingerprinting, using matrix-assisted laser desorption/ionization-time of flight mass spectrometry, and with amino acid sequencing using electrospray ionization tandem mass spectrometry. To improve the identification of low abundant proteins in silver stained 2-DE gels, 2,5-dihydroxybenzoic acid was used instead of α-cyano-4-hydroxycinnamic acid as matrix in the peptide mass fingerprinting procedure; this was demonstrated to give more matching peptide peaks, higher sequence coverage, and higher signal to noise ratio. Altogether 18 different proteins were demonstrated in LDL and/or HDL: three of these (calgranulin A, lysozyme C and transthyretin) have not been identified in LDL before. Apo C-II, apo C-III, apo E, apo A-I, apo A-IV, apo J, apo M, serum amyloid A-IV and α1-antitrypsin were found in both LDL and HDL, while apo B-100 (clone), calgranulin A, lysozyme C and transthyretin were found only in LDL, and apo A-II, apo C-I, and serum amyloid A only in HDL. Salivary α-amylase wass identified only in HDL2, and apo L and glycosylated apo A-II only in HDL3. Many of the proteins occurred in a number of isoforms: in all, 47 different isoform identities were demonstrated. A 2-DE mobility shift assay and deglycosylation experiments were used to demonstrate, for the first time, that apo M in LDL and HDL occurs in five isoforms; three that are both N-glycosylated and sialylated, one that is N-glycosylated but not sialylated and one that is neither N-glycosylated nor sialylated. LDL from obese subjects was found to contain more apo J, apo C-II, apo M, α1-antitrypsin and serum amyloid A-IV than LDL from controls,, and also more of an acidic isoform (pI/Mr; 5.2 / 23 100) of apo A-I. In addition, the new LDLassociated protein transthyretin, was found to be significantly more abundant in LDL from obese subjects. On the other hand, the amounts of apo A-IV and the major isoform of apo A-I (pI/Mr; 5.3 / 23 100) were significantly less. Altogether, these findings (i) illustrate the power of 2-DE and mass spectrometry for detailed mapping of the proteins and their isoforms in human lipoproteins; (ii) demonstrate the presence of a number of new proteins in LDL (calgranulin A, lysozyme C and transthyretin); (iii) give precise biochemical clues to the polymorphism of apo M in LDL and HDL, and; (iv) indicate that obesity is associated with significant changes in the protein profile of LDL. It is concluded that new information on lipoproteins can easily be obtained through a proteomic approach, thus facilitating the development of a new proteomic field: lipoproteomics. Much further investigation in this field is warranted, particularly because newly discovered LDL and HDL proteins may play hitherto unknown role(s) in inflammatory reactions of the arterial wall and evolve as useful biomarkers in cardiovascular disease.

Place, publisher, year, edition, pages
Institutionen för molekylär och klinisk medicin, 2007
Linköping University Medical Dissertations, ISSN 0345-0082 ; 986
LDL, HDL, Proteomik, Atheroskleros, Masspektrometri, 2-DE
National Category
Cell and Molecular Biology
urn:nbn:se:liu:diva-8527 (URN)978-91-85715-47-3 (ISBN)
Public defence
2007-03-29, Aulan, Hälsans Hus, Campus US, Linköpings Universitet, Linköping, 09:00 (English)
Available from: 2007-03-15 Created: 2007-03-15 Last updated: 2009-08-22

Open Access in DiVA

No full text

By organisation
Department of Molecular and Clinical Medicine

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 19 hits
ReferencesLink to record
Permanent link

Direct link