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Zahvaljujući sposobnosti kataliziranja redukcija karbonilnih grupa u prokiralnim spojevima do kiralnih alkohola, koji su važni međuprodukti u proizvodnji lijekova i kemikalija, dehidrogenaze su enzimi od velike industrijske važnosti. U novije vrijeme cilj je industrijsku proizvodnju uskladiti s načelima zelene kemije, stoga se velike količine hlapljivih, zapaljivih i toksičnih organskih otapala nastoje zamijeniti sigurnijim otapalima za ljudsko zdravlje i okoliš. Nova generacija takvih otapala su eutektička otapala koje karakteriziraju niska hlapljivost, biorazgradivost i jednostavna sinteza. Cilj ovog rada bio je ispitati mogućnosti primjene eutektičkih otapala u reakcijama kataliziranim alkohol dehidrogenazom. Pripravljena su različita eutektička otapala, s kolin-kloridom u sastavu, u kojima je ispitana aktivnost te su praćene promjene u konformaciji enzima alkohol dehidrogenaze. U istim je otapalima također praćena stabilnost koenzima NADH i NAD+ koji su potrebni za aktivnost alkohol dehidrogenaze. Eutektička otapala na bazi kolin-klorida s ureom u sastavu najbolje su stabilizirala oba oblika nikotinamidnog koenzima, no niti jedno eutektičko otapalo nije se pokazalo kao povoljan medij za odvijanje enzimske reakcije alkohol dehidrogenaze. Due to their ability to catalyze the reduction of carbonyl groups in prochiral compounds to chiral alcohols, which are important intermediates in the production of pharmaceuticals and chemicals, dehydrogenases are enzymes of great industrial importance. Recently, a tendency is to coordinate industrial production with the principles of green chemistry, so large amounts of volatile, flammable and toxic organic solvents are being replaced by solvents which are safer for human health and the environment. A new generation of such solvents is deep eutectic solvents characterized by low volatility, biodegradability, and easy synthesis. The aim of this study was to investigate the possibilities of using deep eutectic solvents in alcohol dehydrogenase-catalyzed reactions. Various choline-chloride based deep eutectic solvents were prepared in which enzyme activity was measured and changes in the conformation of the enzyme alcohol dehydrogenase were monitored. In the same solvents, the stability of the coenzymes NADH and NAD+ required for alcohol dehydrogenase activity was also monitored. Choline-chloride based deep eutectic solvents containing urea best stabilized both forms of nicotinamide coenzyme, but neither deep eutectic solvent proved to be a suitable medium for the enzymatic reaction of alcohol dehydrogenase. |
