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Lipoprotein study by SEC/LLSD method
Šinglárová, Simona ; Tvrzická, Eva (advisor) ; Staňková, Barbora (referee)
The disorders of the lipid metabolism have to be monitored for a number of socially significant diseases. For the diagnosis of these disorders, it turned out in the last 10 years as very beneficial to determine the particle size of the individual lipoprotein classes, in particular the low-density lipoprotein. Among several known methods, we have chosen gel filtration with the light scattering detector. Lipoprotein fractions were separated by ultracentrifugation from the plasma of four donors. Three biochemical parameters - total cholesterol, triacylglycerol, and total protein - were routinely determined for plasma and for each fraction. The silica column BioBasic SEC 300x7,8 mm was calibrated by the proteins thyroglobulin, ovalbumin and angiotensin II with UV detection (280 nm). These proteins are not suitable (due to the size) for the calibration method SEC-LLSD. Therefore, latex beads of various modifications and sizes were tested. The only usable measurement was obtained for the deep-blue latex beads of the size 55 nm, the others remained retained in the column. The lipoprotein fractions of VLDL and LDL were examined by the SEC-LLSD method at different pH (7.3, 7.5, 7.7, 8.0) and ionic strength (0.1M phosphate buffer, 0.1M phosphate buffer and 0.9% NaCl, 0.05M phosphate buffer and 0.9% NaCl)....
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Regulation of lipoprotein lipase activity in circulation
Zemánková, Kateřina ; Kovář, Jan (advisor) ; Vrablík, Michal (referee)
Lipoprotein lipase (LPL) is a key enzyme in lipoprotein metabolism. The enzyme catalyzes hydrolysis of triacylglycerols (TG) of chylomicrons and of very low density lipoproteins (VLDL). However, the mechanisms involved in the regulation of this protein are not fully understood yet. Therefore, the aim of the theses is to study selected aspects of LPL activity regulation. Recently discovered apolipoprotein A-V (apo A-V) substantially affects triglyceridemia and it is presumed that it may function as LPL activator. However, its concentration in the blood is extremely low and we therefore investigated whether most of apo A-V could be bound to the heparan sulfate proteoglycan (HSPG) of vascular wall similarly to LPL. Intravenous heparin application in healthy volunteers resulted in an expected increase in LPL activity but apo A-V concentration did not change. Our results do not support the hypothesis that most of apo A-V is bound to HSPG of the capillary endothelium. An alcohol consumption plays also a role in LPL regulation - the long-term moderate alcohol consumption is known to increase enzyme activity; on the contrary, it is presumed that LPL activity is inhibited immediately after alcohol consumption. However, the direct evidence for such a premise is missing. The other aim of the theses was to...
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