Cyclodextrin glucanotransferase, produced by Bacillus megaterium, was characterized, and the biochemical properties of the purified enzyme were determined. The substrate specificity of the enzyme was tested with different alpha-1,4-glucans. Cyclodextrin glucanotransferase displayed maximum activity in the case of soluble starch, with a Km value of 3.4 g/L. The optimal pH and temperature values for the cyclization reaction were 7.2 and 60 degrees C, respectively. The enzyme was stable at pH 6.0-10.5 and 30 degrees C. The enzyme activity was activated by Sr2+, Mg2+, Co2+, Mn2+, and Cu2+, and it was inhibited by Zn2+ and Ag+. The molecular mass of cyclodextrin glucanotransferase was established to be 73,400 Da by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, 68,200 Da by gel chromatography, and 75,000 Da by mass spectrometry. The monomer form of the enzyme was confirmed by the analysis of the N-terminal amino acid sequence. Cyclodextrin glucanotransferase formed all three types of cyclodextrins, but the predominant product was beta-cyclodextrin.
A system has been developed for prognosis (?l tar and nicotine content in cigarette smoke. The system is based on the estah/ished corelations between the chemical composition of smoke (in regard to tar and nicotine) and the factors it depends on (the chemical composition of the tobaccos in the blend, the characteristics of the cigarette, the .filters, the papers and the applied ventilation). 1'l1e system allows projection of cigarettes with controlled tar and nicotine content, according to the EU requirements. 111e algorithm represents the sequence of the calculatm:v procedure and includes both the potential 1!/' the tobacco material jiw producing the injurious constituents 1?/ cigarette smoke and the respective corrections in accordance with the used papers andfilters, the variance l?fweight and ventilation of the cigarette.
The activities of secreted and mycelial inhibitors of proteolytic enzymes from fungi of the order Hypocreales have been investigated. Inhibitors of bromelain, papain, and trypsin of low molecular mass (about 1 kDa) and a subtilisin proteinaceous inhibitor with molecular mass of 45 kDa were revealed in the culture liquid of the fungus Tolypocladium cylindrosporum. The subtilisin inhibitor from T. cylindrosporum has antibiotic properties, significantly decreased the activity of purified bacterial enzymes, and prevented the growth of the bacterium Pseudomonas sp. Data suggesting the existence in fungi of the Hypocreales order of two pools of peptidase inhibitors have been obtained.
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