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961.
Attempts to induce enantioselectivity in the catalytic hydrogenation of unsymmetrically substituted aromatics using covalently bound, well known chiral auxiliaries are described. Marked differences in stereoselectivity and rate of hydrogenolysis are noted as a function of the auxiliary used. Enantioselectivities obtained in the resulting cyclohexyl derivatives are rather poor. © 1995 Wiley-Liss, Inc. 相似文献
962.
963.
964.
Shinji Hosoi Mitsuo Satoh Hiromasa Miyaji Tatsunari Nishi Tamio Mizukami Mamoru Hasegawa Seiga Itoh Tatsuya tamaoki 《Cytotechnology》1995,19(1):1-10
Pro-UKS1 was designed as a thrombin-resistant derivative of pro-urokinase (pro-UK) by introducing a glycosylation site using site-directed mutagenesis. An expression plasmid for pro-UKS1, pMo1UKS1SEd1-5, was constructed and introduced into Namalwa KJM-1 cells (Hosoiet al., 1988), and cells resistant to G418 and Methotrexate (MTX) were obtained. Amongst them, the highest pro-UKS1 producer (resistant to 500 nM of MTX), clone 41-8, was selected and further characterized. Clone 41-8 was cultured in serum-free ITPSGF medium (Hosoiet al., 1988). Under the conventional conditions, the concentration of pro-UKS1 reached 26 g ml–1. Addition of glucose and tri-iodothyronine (T3) improved productivity, and the maximal productivity of pro-UKS1 was 67 g ml–1 day–1. In this conditioned medium, content of pro-UKS1 was above 80% of total proteins.Abbreviations BSA
bovine serum albumin
- dhfr
dihydrofolate reductase
- HEPES
4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- kb
kilobase pairs
- kDa
kilodaltons
- MTX
Methotrexate
- PBS
phosphate buffered saline
- pro-UK
pro-urokinase
- SDS-PAGE
sodium dodecyl sulfate-polyacrylamide gel electrophoresis
- T3
tri-iodothyronine
- Tween-PBS
phosphate buffered saline containing 0.05% Tween 80 相似文献
965.
Jo Oldknow Tanya M. Franklin Martin Trick Sharon Allard Laurian S. Robert 《Sexual plant reproduction》1995,8(4):254-255
The DNA sequence data reported have been lodged in the Genbank, EMBL and DDBJ databases under the accession numbers Z21609 and Z26914 相似文献
966.
Roger D. Traub 《Journal of computational neuroscience》1995,2(4):283-289
We constructed a computer model of 128 interneurons, each with multiple dendritic branches and an axonal segment. The model neurons were interconnected by gap junctions between dendritic compartments, as are known to occur in rat and guinea-pig hilar interneurons. The model contained no excitatory synapses. In the presence of low-frequency spontaneous action potentials, the model generated synchronized population bursts, when gap junction resistance was 50 M and there were at least two gap junctions per neuron on average. Population bursts occurred only when the dendrites of model neurons were electrically excitable. Consistent with experiment, somatic hyperpolarization during the population burst uncovered partial spikes. In the model, partial spikes originated in electrically active dendrites driven by coupled dendrites. This model may account for population bursts in hilar interneurons that occur in 4-aminopyridine (4AP) together with blockers of GABAA and excitatory amino acid (EAA) receptors. 相似文献
967.
Marianne Borloo Koen Augustyns Alexander Belyaev Ingrid de Meester Anne-Marie Lambeir Filip Goossens Willy Bollaert Padinchare Rajan Simon Scharpé Achiel Haemers 《Letters in Peptide Science》1995,2(3-4):198-202
Summary A series of azaproline dipeptides with various N-substituents were synthesized as possible active-site-directed inhibitors of two proline-specific serine proteases, dipeptidyl peptidase IV and prolyl oligopeptidase. Compounds with semicarbazide, carbazate, acylhydrazine and sulphonylhydrazine structures were tested. Some compounds show moderate activity, i.e., in the millimolar range. 相似文献
968.
Summary Five mmol ofl-2-oxothiazolidine-4-carboxylate (OTC)/kg of body weight was administered into the stomach of rats, and cysteine levels in tissues and sulfate and taurine excreted in the urine were determined. The cysteine (plus cystine expressed as cysteine) concentration in the liver increased to 170–200% of the original level at 30 min and that in the blood to 160% at 60 min after the OTC administration. These high levels were maintained until 8 h after the administration and decreased gradually thereafter. Excretion of sulfate and taurine increased after the OTC administration and the increase corresponded to 26% and 15%, respectively, of the OTC administered. These findings suggest that at least about 40% of the OTC administered into the stomach was taken up and converted to cysteine, which was metabolized to sulfate and taurine. 相似文献
969.
N. Sewald W. Hollweck K. Mütze C. Schierlinger L. C. Seymour K. Gaa K. Burger B. Koksch H. D. Jakubke 《Amino acids》1995,8(2):187-194
Summary Methodology for the synthesis and incorporation of-trifluoromethyl substituted amino acids into N- and C-terminal position of peptides is described. The incorporation of-trifluoromethyl substituted amino acids into strategical positions of peptides enhances proteolytic stability and lipophilicity. Furthermore, it improves transport rates in vivo and permeability through certain body barriers. 相似文献
970.
We have used antibodies directed against a unique portion of the Drosophila POU domain protein Cfla to localize its sites of expression in developing embryos. Cfla protein is first detected during germ band extension in the tracheal placodes and in the midline mesectoderm cells. Tracheal expression continues throughout embryonic development, especially in the main longitudinal tracheal trunks. Additional sites of high Cfla expression are in the anterior portion of the hindgut, the roof of the stomodeum, a subset of central nervous system cells, the oenocytes, and the ring gland. In addition, Cfla expression was localized in embryos mutant for several loci involved in determining fate along the midline of the CNS and the tracheal system. Cfla midline cell expression is dependent on proper single-minded gene function, and Cfla either regulates or acts in parallel to the genes pointed and rhomboid during midline CNS and tracheal development. 相似文献