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Yang Cai, Ph.D - Research
Projects
Proteomics refers to the systematic
characterization of cellular and sub-cellular protein composition,
which is the core of the functional genomics in the post-genome
era. We employ and investigate several complementary fractionation
and mass spectrometry (MS) approaches to increase the proteomic
analysis coverage as well as the protein quantification dynamic
range. Collectively, the complementary MS-based proteomic approaches
provide validated qualitative and quantitative data sets for better
characterization of a proteome. Bio-informatic tools are also
employed in the interpretation, integration, validation and storage
of the huge proteomics data sets, from which abundant information
can be derived to elucidate protein profile, protein function
(including post-translational modification, protein-protein interaction,
protein-ligand interaction, protein activity, localization and
degradation) and protein (protein complex) structure.
Carbohydrates play important roles in many essential
biological processes. Yet this type of bio-molecule and its derivatives
are among those most difficult to characterize. We investigate
and employ highly sensitive mass spectrometry based methods coupled
with various separation tools to systematically analyze oligosaccharides
extracted from various cellular compartments. Carbohydrates can
be roughly divided into two categories: acidic and neutral. In
negative ion mass spectrometry, acidic oligosaccharides can be
easily deprotonated and detected in the form of anions; neutral
oligosaccharides, though lack of apparent deprotonation site,
can form detectable anionic adducts with small inorganic anions.
Method development for carbohydrate characterization in our lab
is focused on the analysis of both neutral and acidic oligosaccharides
in a single experiment of on-line liquid chromatography (LC) negative
ion electrospray mass spectrometry (ES-MS) without switching the
polarity of the mass analyzer.
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