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- Förster, A, et al.
(author)
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Baseline characterization of the CO2SINK geological storage site at Ketzin, Germany
- 2006
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In: Environmental Geosciences. - : American Association of Petroleum Geologists AAPG/Datapages. - 1075-9565 .- 1526-0984. ; 13:3, s. 145-161
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Journal article (peer-reviewed)abstract
- Since April 2004, preparatory work prior to CO2injection hasbeen conducted in the CO2SINK Project, the European Union’sfirst research and development activity on the in-situ testing ofgeological storage of CO2near the town of Ketzin, Germany.Carbon dioxide will be injected into a saline aquifer of the TriassicStuttgart Formation in an anticlinal structure of the northeastGerman Basin. The drilling of one injection and two observationwells will commence at the end of 2006. The predrilling phasefocuses on the baseline geological parameters of the anticline. TheStuttgart Formation is lithologically heterogeneous; it consists ofsandy channel-(string)-facies rocks, with good reservoir propertiesalternating with muddy flood-plain-facies rocks of poor reservoirquality. Playa-type rocks form the immediate cap rock above theCO2SINK reservoir. A geostatistical approach has been applied todescribe the reservoir architecture between and beyond well con-trol. This model forms the basis for the generation of reservoir-dynamic models of CO2injection that assist in the planning ofinjection operations and in the understanding of CO2plume evo-lution. A verification of the geometry of the reservoir and thestructural situation of its overburden is expected from a three-dimensional baseline seismic survey that was conducted in theautumn of 2005. Laboratory experiments under simulated in-situconditions were performed to evaluate the geophysical signatureof rocks saturated with CO2. The chemical composition of thegroundwater and the CO2flux in the soil were analyzed across theKetzin anticline, providing the baseline for a monitoring programduring and after injection of CO2, targeted at the detection ofpotential CO2leakage from the storage reservoir.
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- Kristensen, Kristian K., et al.
(author)
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Unfolding of monomeric lipoprotein lipase by ANGPTL4 : Insight into the regulation of plasma triglyceride metabolism
- 2020
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In: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 117:8, s. 4337-4346
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Journal article (peer-reviewed)abstract
- The binding of lipoprotein lipase (LPL) to GPIHBP1 focuses the intravascular hydrolysis of triglyceride-rich lipoproteins on the surface of capillary endothelial cells. This process provides essential lipid nutrients for vital tissues (e.g., heart, skeletal muscle, and adipose tissue). Deficiencies in either LPL or GPIHBP1 impair triglyceride hydrolysis, resulting in severe hypertriglyceridemia. The activity of LPL in tissues is regulated by angiopoietin-like proteins 3, 4, and 8 (ANGPTL). Dogma has held that these ANGPTLs inactivate LPL by converting LPL homodimers into monomers, rendering them highly susceptible to spontaneous unfolding and loss of enzymatic activity. Here, we show that binding of an LPL-specific monoclonal antibody (5D2) to the tryptophan-rich lipid-binding loop in the carboxyl terminus of LPL prevents homodimer formation and forces LPL into a monomeric state. Of note, 5D2-bound LPL monomers are as stable as LPL homodimers (i.e., they are not more prone to unfolding), but they remain highly susceptible to ANGPTL4-catalyzed unfolding and inactivation. Binding of GPIHBP1 to LPL alone or to 5D2-bound LPL counteracts ANGPTL4-mediated unfolding of LPL. In conclusion, ANGPTL4-mediated inactivation of LPL, accomplished by catalyzing the unfolding of LPL, does not require the conversion of LPL homodimers into monomers. Thus, our findings necessitate changes to long-standing dogma on mechanisms for LPL inactivation by ANGPTL proteins. At the same time, our findings align well with insights into LPL function from the recent crystal structure of the LPL•GPIHBP1 complex.
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