Freshwater biodiversity has been threatened by eutrophication due to excessive nutrients in the environment. Releasing the freshwater species from such pressures requires efforts from industry and... Show moreFreshwater biodiversity has been threatened by eutrophication due to excessive nutrients in the environment. Releasing the freshwater species from such pressures requires efforts from industry and manufacturers to avoid emissions to vulnerable and high-risk regions. The first step is to know which nutrient influences where and the effects thereof on species loss. These impacts can be assessed by methods of life cycle impact assessment (LCIA). This thesis contributes to such knowledge by improving the LCIA method, for instance, by developing more regionalized and comprehensive indicators as well as adding the consideration of both phosphorus (P) and nitrogen (N) and which of these two nutrients is limiting. Show less
In this thesis an activity-based probe was discovered that could visualize the activity of PLAATs. With an optimized gel-based ABPP assay in hand, screening of a compound library led to the... Show moreIn this thesis an activity-based probe was discovered that could visualize the activity of PLAATs. With an optimized gel-based ABPP assay in hand, screening of a compound library led to the discovery of alpha-ketoamides as a hit for PLAAT3. Through extensive structural modifications of the hit, LEI110 was identified as the most potent inhibitor (Ki = 20nM) for PLAAT3. LEI110 reduced cellular arachidonic acid levels in PLAAT3 overexpressing U2OS cells and oleic acid-induced steatosis in human HepG2 cells. Gel-based ABPP and chemical proteomics showed that LEI110 is a selective pan-inhibitor of the Hrasls-family of thiol hydrolases (i.e. PLAAT2, PLAAT3 and PLAAT5). LEI110 could be an excellent starting point for the structure-based drug development of novel molecular therapies for obesity and/or common cold. In addition, a competitive, gel-based ABPP method for PLA2G4E using TAMRA-FP was successfully developed and applied to screen a focused library of lipase inhibitors. This resulted in the discovery of two clusters of inhibitors with different scaffolds. Optimization of the potency and selectivity of the inhibitors is required to the study of the biological role of PLA2G4E in an acute and dynamic setting with these novel tools. Together these novel chemical tools and methods will allow for a better understanding of the biosynthesis of the NAPEs and to study their biological role. Show less
