Virtual two-dimensional gel electrophoresis of high-density lipoproteins.
High-density lipoproteins (HDLs) isolated by immunoaffinity chromatography and separated by immobilized pH gradient-isoelectric focusing (IPG-IEF) were examined by mass spectrometry directly, applying a new proteomics technology, virtual two-dimensional (2-D) gel electrophoresis. A preliminary examination of HDL particles has revealed at least 42 unique masses for protein species with isoelectric points between pH 5.47-5.04, some of which have not been observed previously. By delivering masses of intact proteins from complex cellular mixtures in a format that correlates directly to classical 2-D gel analyses, virtual 2-D gel electrophoresis constitutes a general discovery tool to expose and monitor protein isoforms and post-translational modifications. Furthermore, its general ability to deliver ions from sub-picomole level proteins enmeshed in complex cellular mixtures potentially fulfills the need of top-down proteomics to obtain intact protein ions from microscale samples. Additional comparison of such data to 2-D gel analyses and their identified proteins may elucidate the functions of the individual apolipoprotein components and the cardioprotective effects of HDL.
Ogorzalek Loo
Rachel R
RR
Department of Biological Chemistry, University of California, Los Angeles, CA 90095, USA. RLoo@mednet.ucla.edu
Yam
Lang
L
Loo
Joseph A
JA
Schumaker
Verne N
VN
D016632:Apolipoprotein A-I / Q000032:analysis* / Q000737:chemistry; D015180:Electrophoresis, Gel, Two-Dimensional / Q000379:methods*; D006801:Humans; D007525:Isoelectric Focusing / Q000379:methods*; D008075:Lipoproteins, HDL / Q000032:analysis* / Q000097:blood; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
D016632:Apolipoprotein A-I; D008075:Lipoproteins, HDL