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Dehydrogenazy alkoholowe pochodzenia mikrobiologicznego : właściwości i ich zastosowanie

100%

Szczepańska E. , Boratyński F.

tom [Z] 68, 11-12

1049--1071

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.

Aktywność dehydrogenazy alkoholowej surowicy krwi w różnych wartościach pH w przebiegu alkoholizmu

100%

Chrostek L. , Szmitkowski M.

nr 5

Enancjoselektywna enzymatyczna desymetryzacja katalizowana oksydoreduktazami. Dehydrogenazy w reakcji redukcji. Część I

100%

Kołodziejska R. , Karczmarska-Wódzka A. , Tafelska-Kaczmarek A. , Studzińska R. , Wróblewski M. , Augustyńska B.

tom [Z] 68, 9-10

763--782

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.

Aktywnosc dehydrogenazy mleczanowej ludzkich erytrocytow w obecnosci wybranych inhibitorow dehydrogenazy alkoholowej

59%

Dudka J. , Burdan F. , Madej B. , Tokarska E. , Klepacz R. , Korobowicz E.

nr 3

229-234

W pracy oceniono wpływ cymetydyny, EDTA, 4-metylopirazolu oraz etanolu i metanolu na aktywność dehydrogenazy mleczanowej. Badania przeprowadzono in vitro z enzymem otrzymanym z erytrocytów ludzkich.

The aim of the study was to evaluate the effect of alcohol dehydrogenase (ADH; E.C. 1.1.1.1) inhibitors and substrates: Cimetidine, 4-methylpyrazole (4MP), EDTA, ethanol and methanol on lactate dehydrogenase (LDH; E.C. 1.1.1.27) activity. The activity of LDH was spectrophotometrically determined in in-vitro prepared diluted hemolysates obtained from human erythrocytes with mentioned compounds at the concentrations 0.01, 0.1, 1.0 mM of Cimetidine, EDTA, 4MP and 12.5, 25.0, 50.0 mM of ethanol and methanol. The reaction was conducted at 37°C in pH 7.5 and changes of optical density was measured at λ=340nm. LDH activity was significantly inhibited by 0.10 mM (p<0.05) and 1 .OmM (p<0.01 ) of Cimetidine and EDTA. There were no observed any significant changes vcontrol in LDH activity when 4MP, ethanol or methanol was added to environment of reaction.