Staff Members of the Institute of Biochemistry, TU - Institut für ...

an important subfamily of the oxidized phospholipids containing long hydrocarbon chains in
position sn-1 and short polar acyl residues in position sn-2 of the glycerol backbone. The
respective compounds trigger an intracellular signaling network including sphingomyelinases,
(MAP) kinases and transcription factors thereby inducing proliferation or apoptosis of
vascular cells. Both phenomena largely depend on the specific action of sphingolipid
mediators that are acutely formed upon cell stimulation by the oxidized lipids. Fluorescence
microscopic studies on labeled lipid analogs revealed that the short-chain
phosphatidylcholines are easily transferred from the aqueous phase into the cell plasma
membrane and eventually spread throughout the cells. Under these circumstances, the biologi-
cally active compounds are very likely to interfere
directly with various signaling components inside
the cells, which finally decide about cell growth or
death. Investigations are being performed on the
levels of the lipidome, the apparent enzyme
activities, the proteome an the transcriptome to find
the primary molecular targets and their downstream
elements that are the key compnents of lipid-induced
cell death.
1.2. Oxidative stress and antioxidants
Antioxidants protect biomolecules against
oxidative stress and thus, may prevent its
pathological consequences. Specific fluorescent
markers have been established for high-throughput
screening of lipid and protein oxidation and its
inhibition by natural and synthetic antioxidants.
These methods can also be used for the
determination of antioxidant capacities of
biological fluids (e.g. serum) and edible oils. A
prominent example is pumpkin seed oil which
contains a variety of antioxidants (e.g. tocopherols
and phenolic substances) and other secondary plant
components that possess useful biological
properties.
2. Functional proteomic analysis of lipolytic enzymes
The functional properties of lipases and phospholipases are the subject of our studies in the
framework of two joint research programs (GOLD-Genomics of Lipid-associated Disorders at
KFU Graz and the Research center Applied Biocatalysis at TU Graz). Lipolytic enzymes
catalyze intra- and extracellular lipid degradation. Dysfunctions in lipid metabolism may lead
to various diseases including obesity, diabetes or atherosclerosis. In chemistry, lipases and
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