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1
Content available remote Chemia znikającego alkoholu: Twoje ciało winowajcą czy ofiarą?
PL
Alkohol, dzięki swoim właściwościom stosowany jest jako popularna wśród społeczeństwa używka, należy jednak brać pod uwagę fakt możliwości pojawienia się nieprzyjemnych skutków jego działania na organizm w postaci kaca kolejnego dnia. Odpowiedzialny za to jest między innymi jeden z metabolitów alkoholu, a mianowicie aldehyd octowy. Jego poziom po spożyciu alkoholu etylowego jest zależny od naszego poziomu dehydrogenazy aldehydowej, w większości przypadków jest on za niski by nie odczuwać objawów kaca. Do typowych objawów tej przypadłości należą: zmęczenie, pragnienie, ból głowy, problemy ze snem, podrażnienie przewodu pokarmowego, problemy sensoryczne, problemy z nastrojem, pocenie i drżenie. Na intensywność kaca ma wpływ kilka czynników i to zarówno przed spożywaniem jak i po. Ale jedynym w stu procentach skutecznym sposobem jest nie picie alkoholu lub ograniczenie spożycia do absolutnego minimum. Pomimo tego, że istnieje kilka mitów o cudownych sposobach na kaca takich jak mocna kawa, zimny prysznic, kolejność picia alkoholi lub klin, to żaden z nich nie jest tak naprawdę skuteczny i co najwyżej łagodzi część objawów.
EN
Alcohol in our culture allows us to make friends, but do not overdo it because we can experience a hangover the next day. One of the metabolites of alcohol, namely acetaldehyde, is responsible for this. Its level after consuming ethyl alcohol depends on our level of aldehyde dehydrogenase, in most cases it is too low not to feel the symptoms of a hangover. Typical symptoms of this condition include fatigue, thirst, headache, sleep problems, gastrointestinal irritation, sensory problems, mood problems, sweating and tremors. Several factors affect the intensity of a hangover, both before and after eating. But the only one hundred percent effective way is not to drink alcohol or to limit consumption to the absolute minimum. Although there are several myths about hangover miraculous remedies such as strong coffee, cold showers, the order of drinking alcohols or wedges, none of them are really effective and only relieve some of the symptoms.
EN
Enzymes act as biocatalysts whether are also mediating in all anabolic and catabolic pathways, playing an extremely important role in the cells of all life forms. Catalytic potential of oxidoreductases is most commonly used in reduction reactions. Dehydrogenases and reductases catalyze the reversible desymmetrization reactions of meso and prochiral carbonyl compounds and alkenes. The oxidoreductase- catalyzed reactions require cofactors to initiate catalysis. In most cases, it is nicotinamide adenine dinucleotide (NADH) or its phosphorylated derivative (NADPH), which acts as a hydride donor. The necessity of employing expensive cofactors was, for the long time, one of the main limitations to the use of dehydrogenases. This problem was solved by developing a regeneration system of a cofactor in the reaction environment. Various systems are used for the cofactor recycling. In the case of a carbonyl compound reduction, an irreversible oxidation of formic acid to carbon dioxide is most frequently used. In this paper, selected examples of whole-cell and isolated enzymes applications in the carbonyl compound reduction are discussed. The application of baker’s yeast, microorganisms and dehydrogenases in enantioselective enzymatic desymmetrization (EED) of prochiral ketones leads to a broad spectrum of chiral alcohols used as intermediates in the syntheses of many pharmaceuticals and compounds presenting a potential biological activity.
EN
Biotransformations involve mainly microorganisms or individual enzymes applied to catalyze chemical reactions [1]. This field of science is particularly important, because it allows to obtain optically active compounds, which are valuable raw materials for pharmaceutical (Fig. 3, Fig. 6, Fig. 20, Fig. 21), wood and paper (Fig. 18), food (Fig. 4), textile (Fig. 12), cosmetic (Fig. 14) industries and environmental protection (Fig. 19). Oxidoreductases, in particular alcohol dehydrogenases (E.C.1.1.1.1, ADH) are valuable biocatalysts enabling to obtain enantiomerically pure products. These enzymes, commonly found in nature, catalyze both oxidation and reduction reactions [3]. Described dehydrogenases descend from mesophilic, psychrophilic and thermophilic microorganisms. The increasing application of thermophiles is due to their exceptional resistance against heat and organic solvents. The article describes and explains how microbial ADH’s interact with NAD+/NADH or NADP+/NADPH and present those enzymes which catalyze reactions with both forms of cofactors. The alcohol dehydrogenases from yeast are particularly commonly used [9–14]. Bacterial enzymes, among them ADH isolated from Thermoanaerobacter brockii [47–51], are widely distributed too. In addition, the literature describes a number of (R)-specific ADH’s from Lactobacillus kefir [40–42], L. brevis [45, 46], Leisofonia sp. [20] Pseudomonas fluorescens [23] and (S)- -specific ADH’s from Rhodococcus erythropolis [15, 16], Thermus sp. [30], Sulfolobus solfataricus [23, 28] and many others.
4
Content available remote Physiology and metabolism of crabtree-negative yeast Debaryomyces occidentalis
EN
This paper is focused on the physiology and metabolism of non-conventional yeasts, especially these belonging to Debaryomyces (syn. Schwanniomyces) occidentialis. In these Crabtree-negative yeast strains, oxygen limitation induces alcoholic fermentation as well as activity of the key fermentative enzymes, pyruvate decarboxylase (PDC) and alcohol dehydrogenase (ADH).
PL
W oparciu o dane literatury przedstawiono fizjologię i metabolizm niekonwencjonalnych drożdży należących do Debaryomyces occidentalis. U tych drożdży tlen indukuje proces fermentacji i aktywność kluczowych enzymów: dekarboksylazy pirogronianowej (PDC) i dehydrogenazy alkoholowej (ADH).
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