PubMed · 2314242
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
S Englard, S Seifter. 1990. Precipitation techniques.. https://doi.org/10.1016/0076-6879(90)82024-v
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Persimmon fruit polyphenol oxidase (PPO) was partially purified using a combination of phase partitioning with Triton X-114 and ammonium sulfate fractionation between 50 and 75%. The enzyme, which showed both monophenolase and diphenolase activities, was partially purified in a latent form and could be optimally activated by the presence of 1 mM sodium dodecyl sulfate (SDS) with an optimum pH of 5.5. In the absence of SDS, the enzyme showed maximum activity at acid pH. SDS-PAGE showed the presence of a single band when L-DOPA was used as substrate. The apparent kinetic parameters of the latent enzyme were determined at pH 5.5, the V(m) value being 15 times higher in the presence of SDS than in its absence, whereas the K(M) was the same in both cases, with a value of 0.68 mM. The effect of several inhibitors was studied, tropolone being the most active with a K(i) value of 0.45 microM. In addition, the effect of cyclodextrins (CDs) was studied, and the complexation constant (K(c)) between 4-tert-butylcatechol (TBC) and CDs was calculated using an enzymatic method. The value obtained for K(c) was 15580 M(-1).
Three different crystal forms of the swine vesicular disease virus (SVDV), isolate SPA/2/'93, were obtained by the hanging-drop vapour-diffusion technique using ammonium sulfate and sodium/potassium phosphate as precipitants. Monoclinic crystals, space group C2, with unit-cell parameters a = 473.7, b = 385.3, c = 472.8 A, beta = 100.4 degrees, contain one virus pArticle in the crystal asymmetric unit and diffract to 3.0 A resolution. A second type of crystals had a cubic morphology and diffracted beyond 2.6 A resolution. These crystals belong to a primitive orthorhombic space group, with unit-cell parameters a = 319.6, b = 353.8, c = 377.7 A, and contain half a virus pArticle in the asymmetric unit. A third type of crystals, with a prismatic shape and belonging to space group I222, was also obtained under similar crystallization conditions. These latter crystals, with unit-cell parameters a = 318.3, b = 349.9, c = 371.7 A, diffract to at least 3.0 A resolution and contain 15 protomers per asymmetric unit; this requires that three perpendicular crystal twofold axes coincide with three of the viral pArticles' dyad axes.
Electrodialysis experiments of the lysine fermentation waste were performed to generate demineralized feed and ammonium sulfate, which can be utilized as a fertilizer and an animal feed, respectively. The electrodialysis performances were compared for different ion exchange membranes in terms of ammonium sulfate removal rate, resistance and conductivity change. Analysis of fouling phenomena revealed that organics fouled ion exchange membranes reversibly in electrodialysis of the fermentation waste. In this study, mitigation of membrane fouling with the pulsed electric field was examined for the electrodialysis of the fermentation waste containing strong foulants. The half-wave power reduced membrane fouling significantly. For a quantitative measure of the membrane fouling tendency, a membrane fouling index for electrodialysis was used. This study showed the potential use of pulsed power as an effective fouling mitigation method for the electrodialysis of fermentation waste.