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111.
Isoelectric points differing by 1 to 2 pH units are measured for horseradish peroxidase and lactoperoxidase depending upon the technique of isoelectric focusing, namely, the density gradient technique or systems stabilized by either granulated (Sephadex, Bio-Gel) or compact polyacrylamide gels. Conditions standardized for the determination of pI values of selected pH marker proteins proved inadequate for the predominant isoenzyme of horseradish peroxidase which requires an excessively long focusing time to attain the steady state. Carbon dioxide interferes with the determination of pI values >8.2 to 8.3. Thin-layer isoelectric focusing in a CO2-free atmosphere followed by pH measurements also in a CO2-free atmosphere, yields for alkaline marker proteins and the predominant peroxidase isoenzyme, pI values in excellent agreement with these found by the density gradient technique. The isoionic point of the predominant peroxidase isoenzyme determined by ion exchange desalting is identical with the isoelectric point found by density gradient and thin-layer isoelectric focusing in a CO2-free atmosphere. 相似文献
112.
Gerd Moeckel Matthias Keil Monica Hollstein Bertold Spiegelhalder Helmut Bartsch Jürgen Brickmann 《Journal of molecular modeling》1997,3(9):382-385
The inactivation of the p53 tumor suppressor function by single missense point mutations is found in almost half of human tumors. Most p53 mutation hotspots are at the DNA binding interface, shown in the three-dimensional (3D) structure of a p53-DNA complex crystallized by Pavletich and coworkers [1]. We have investigated the influence of mutations on the predicted specific DNA binding capacities of p53 by using molecular modeling to compare biochemical properties of wild type and mutated p53 complexed to DNA. Changes in local properties e.g. electrostatic potential or hydrophilic/lipophilic properties, combined with the steric interferences, lead to a loss of specific binding and presumably disables the tumor suppressor function. The 3D-structures combined with molecular biochemical properties of the wild type and the mutated p53-DNA complex can be transferred by the use of the Virtual Reality Modeling Language (VRML). Special tools e.g. space buttons allow users the interactive exploration of structures, properties, and additional information via internet. Electronic Supplementary Material available. 相似文献
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114.
Endothelial progenitor cells: Characterization, <Emphasis Type="Italic">in vitro</Emphasis> expansion,and prospects for autologous cell therapy 总被引:1,自引:0,他引:1
Injection of hematopoietic stem cells or endothelial progenitor cells (EPCs) expanded ex vivo has been shown to augment neovascularization in adult patients, but the precise origin and identity of the cell population
responsible for these clinical benefits are controversial. The limited quantity of EPCs in the circulation has been the main
obstacle to clinical trials. Several authors have therefore attempted to expand these cells ex vivo in order to obtain a homogeneous cell therapy product. One possible means of expanding EPCs ex vivo is to activate the thrombin receptor PAR-1 with the specific peptide SFLLRN. Indeed, PAR-1 activation promotes cell proliferation
and C-X-C chemokine receptor type 4 (CXCR4) dependent migration and differentiation, with an overall angiogenic effect. This
review summarizes the results and rationale of clinical trials of angiogenic therapy, the nature of EPCs, the different methods
of ex vivo expansion, and current methods of quantification. 相似文献
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116.
Hans-Joachim Emmerich Martin Saft Leonie Schneider Dennis Kock Alfred Batschauer Lars-Oliver Essen 《Nucleic acids research》2020,48(22):12845
Photolyases are ubiquitously occurring flavoproteins for catalyzing photo repair of UV-induced DNA damages. All photolyases described so far have a bilobal architecture with a C-terminal domain comprising flavin adenine dinucleotide (FAD) as catalytic cofactor and an N-terminal domain capable of harboring an additional antenna chromophore. Using sequence-similarity network analysis we discovered a novel subgroup of the photolyase/cryptochrome superfamily (PCSf), the NewPHLs. NewPHL occur in bacteria and have an inverted topology with an N-terminal catalytic domain and a C-terminal domain for sealing the FAD binding site from solvent access. By characterizing two NewPHL we show a photochemistry characteristic of other PCSf members as well as light-dependent repair of CPD lesions. Given their common specificity towards single-stranded DNA many bacterial species use NewPHL as a substitute for DASH-type photolyases. Given their simplified architecture and function we suggest that NewPHL are close to the evolutionary origin of the PCSf. 相似文献
117.
Cold/Warm stenothermic freshwater macroinvertebrates along altitudinal and latitudinal gradients in Western South America: A modern approach to an old hypothesis with updated data 下载免费PDF全文
Daniel A. Dos Santos Carlos Molineri Carolina Nieto María C. Zuñiga Daniel Emmerich Pablo Fierro Pablo Pessacq Blanca Rios‐Touma Javier Márquez Daniela Gomez Frederico F. Salles Andrea C. Encalada Romina Príncipe Graciela C. Gómez Claudio Valdovinos Zarges Eduardo Domínguez 《Journal of Biogeography》2018,45(7):1571-1581
118.
José Mordoh Bertold R. Fridlender 《Biochemical and biophysical research communications》1975,67(3):888-896
Cells from a patient with acute lymphoblastic leukemia contained an altered nuclear DNA polymerase. This enzymatic activity differs from the normal enzyme in its KCl sensitivity, heat stability and reactivity with antibody against HeLa cytoplasmic DNA polymerase-α. The results also show that in these leukemic cells the cytoplasmic DNA polymerase-α is different to the nuclear DNA polymerase. 相似文献
119.
In the haemolymph of adult female locusts six different lipoprotein fractions have been demonstrated by means of isoelectric focusing. One of these binds injected 3H-Cecropia juvenile hormone. The carrier protein is a yellow lipoprotein with a molecular weight of approximately 220,000 daltons and an isoelectric point of pH 6·8. The binding of the hormone to the protein is stable during gel filtration over Sephadex G-25 and during dialysis for 24 hr against phosphate buffer pH 7·0.The hormone is quickly metabolized in the locusts. In the haemolymph were found more polar compounds such as 10-epoxy-7-ethyl-3,11 dimethyl-2,6-tridecadienoic acid and the corresponding dioldienoic acid.Both compounds were not bound by the pH 6·8 carrier lipoprotein under in vivo conditions. 相似文献
120.