Universität Stuttgart

Permanent URI for this communityhttps://elib.uni-stuttgart.de/handle/11682/1

Browse

Filters

2002 - 20032

Settings

Subject: search.filters.subject.540Institute: search.filters.UBSInstitut.Institut für Technische BiochemieInstitute: search.filters.UBSInstitut.Sonstige EinrichtungAuthor: search.filters.author.Henke, Erik

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Activity of lipases and esterases towards tertiary alcohols : new insights into structure-function relationships
    (2002) Henke, Erik; Pleiss, Jürgen; Bornscheuer, Uwe Theo
    Hydrolytic enzymes are versatile biocatalysts and find increasing applications in organic synthesis and a considerable number of industrial processes using these enzymes have been commercialized. Within this class, lipases (E.C. 3.1.1.3) and carboxyl esterases (E.C. 3.1.1.1) are frequently used as they accept a broad range of non-natural substrates, are usually very stable in organic solvents and exhibit good to excellent stereoselectivity.
  • Thumbnail Image
    ItemOpen Access
    The molecular mechanism of enantiorecognition of tertiary alcohols by carboxylesterases
    (2003) Henke, Erik; Bornscheuer, Uwe Theo; Schmid, Rolf D.; Pleiss, Jürgen
    Carboxylesterases containing the sequence motif GGGX catalyze hydrolysis of esters of chiral tertiary alcohols, albeit at only low to moderate enantioselectivity towards three model substrates (linalyl acetate, methyl-1-pentin-1-yl acetate, 2-phenyl-3-butin-2-yl acetate). In order to understand the molecular mechanism of enantiorecognition and to improve enantioselectivity towards this interesting substrate class, the interaction of both enantiomers with the substrate binding sites of acetylcholinesterases and p-nitrobenzyl esterase from Bacillus subtilis was modeled and correlated to experimental enantioselectivity. For all substrate-enzyme pairs, enantiopreference and ranking by enantioselectivity could be predicted by the model. In p-nitrobenzyl esterase, one of the key residues in determining enantioselectivity was G105: exchange of this residue by alanine led to a six-fold increase of enantioselectivity (E=19) towards 2-phenyl-3-butin-2-yl acetate. However, the effect of this mutation is personalized: towards the substrate linalyl acetate, the same mutant had a reversed enantiopreference. Thus, depending on the substrate structure, the same mutant had either increased enantioselectivity or opposite enantiopreference compared to wild type enzyme.