für Naturforschung in cooperation with the Max Planck Society for the Advancement of Science under a Creative Commons Attribution 4.0 International License. Dieses Werk wurde im Jahr 2013 vom Verlag Zeitschrift für Naturforschung in Zusammenarbeit mit der Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V. digitalisiert und unter folgender Lizenz veröffentlicht: Creative Commons Namen...

Ferritin has a high capacity as an iron store, incorporating some 4500 iron atoms as a microcrystalline ferric oxide hydrate. Starting from apoferritin, or ferritin of low iron content, Fe2+ and an oxidizing agent, the uptake of iron can be recorded spectrophotometrically. Progress curves were obtained and the reconstituted ferritin was shown by several physical methods to be similar to natural...

Experimental studies on the cleavage of various RNA molecules--poly(U), 3',5''-UpU, 2',5''-UpU, and 3',5''-ApA--catalyzed by imidazole buffers show that there is a sequential bifunctional mechanism. One catalyst species converts the substrate to an intermediate phosphorane, and the second catalyst converts the phosphorane to cleavage products. Detailed steady-state kinetics are presented to det...

Bovine lens cytoplasmic aldehyde dehydrogenase exhibits Michaelis-Menten kinetics with acetaldehyde, glyceraldehyde 3-phosphate, p-nitrobenzaldehyde, propionaldehyde, glycolaldehyde, glyceraldehyde, phenylacetylaldehyde and succinic semialdehyde as substrates. The enzyme was also active with malondialdehyde, and exhibited an esterase activity. Steady-state kinetic analyses show that the enzyme ...

Bioleaching was used to mobilize Cu, Zn and Ni from waste printed circuit boards (WPCBs) and eliminate hazardous metal species from these wastes. Pulp density (PD) and medium culture are two effective factors which have been optimized in this paper. The bacteria Acidithiobacillus ferrooxidans (A. ferrooxidans) and Acidithiobacillus thiooxidans (A. thiooxidans) and their mixture were grown and a...

objectives: this paper describes further improvement and preliminarily evaluation of a novel viscoelastic ankle-foot prosthesis prototype. the objective was to control the ankle hysteresis at slow and normal walking speeds. methods: inspired by the ankle biomechanics, in which the hysteresis differs based on the gait speeds, a manually damping control mechanism imbedded in the prosthesis for ad...

classical xerogels are robust, inexpensive and nontoxic materials with low-ordered nanoporous structures. in water streams where the ph is higher than the point of zero charge, the surface of classical xerogels such as tetraethoxy orthosilan (teos) xerogel is negatively charged. it was assumed that a xerogel can work as a strong adsorbent for metal ions without further modification. therefore, ...

The mechanism that has been proposed for glyoxalase II [36] is summarized in Figure 3. It involves direct nucleophilic attack of an active-site histidine on the thiol ester substrate to form an acyl-imidazole intermediate which then rapidly hydrolyses. This is consistent with the known susceptibility of thiol esters to aminolysis and with the lability of acyl-imidazoles [47].

The HCCI combustion process is initiated due to auto-ignition of fuel/air mixture which is dominated by chemical kinetics and therefore fuel composition has a significant effect on engine operation and a detailed reaction mechanism is essential to analysis HCCI combustion. A single zone-model permits to have a detailed chemical kinetics modeling for practical fuels. In this study a single-zone ...

the hcci combustion process is initiated due to auto-ignition of fuel/air mixture which is dominated by chemical kinetics and therefore fuel composition has a significant effect on engine operation and a detailed reaction mechanism is essential to analysis hcci combustion. a single zone-model permits to have a detailed chemical kinetics modeling for practical fuels. in this study a single-zone ...