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351.
Helen Pappa Huiying Li Munirathinam Sundaramoorthy David Arciero Alan Hooper Thomas L. Poulos 《Journal of structural biology》1996,116(3):429-431
The di-heme peroxidase (cytochrome c553 peroxidase) fromNitrosomonas europaeahas been crystallized in a form suitable for high-resolution X-ray structure determination. A complete data set was obtained to 2.5 Å and the data were indexed in space group P21witha= 88.79 Å,b= 55.93 Å,c= 144.37 Å, β = 103.87°. The self-rotation function indicates one homodimer per asymmetric unit. 相似文献
352.
The biosynthesis of choline plasmalogen by ox heart 总被引:1,自引:0,他引:1
353.
K Barlos D Gatos S Kapolos C Poulos W Sch?fer W Q Yao 《International journal of peptide and protein research》1991,38(6):555-561
The carboxyl terminal dipeptide amide, Fmoc-Asp-Phe-NH2, of gastrin and cholecystokinin (CCK) has been attached in high yield through its free side chain carboxyl group to the acid labile 2-chlorotrityl resin. The obtained peptide resin ester has been applied in the solid phase synthesis of partially protected (Leu15)-gastrin I utilising Fmoc-amino acids. Quantitative cleavage of this peptide from resin, with the t-butyl type side chain protection intact is achieved using mixtures of acetic acid/trifluoroethanol/dichloromethane. Under the same conditions complete detritylation of the tyrosine phenoxy function occurs simultaneously. Thus, the solid-phase synthesis of peptides selectively deprotected at the side chain of tyrosine is rendered possible by the use of 2-chlorotrityl resin and Fmoc-Tyr(Trt)-OH. The efficiency of this approach has been proved by the subsequent high-yield synthesis of three model peptides and the CCK-octapeptide. 相似文献
354.
JÖRG THOMAS EPPLEN BRIGITTE KUNZ GERD WIECZOREK-ENGELKEN WOLFGANG ENGEL JÖRG SCHMIDTKE 《Differentiation; research in biological diversity》1981,20(1-3):124-130
Enzymatic digestion of the interstitial tissue of early juvenile and adult rat testes resulted in an enrichment of the Leydig cell population. The cells of the intertubular preparation from adult testes were separated by centrifugal elutriation, according to differences in sedimentation velocity, a counter-flow centrifugation technique leading to 70% Leydig cell purity. Using this approach, it was possible to demonstrate that Leydig cells from adult testes contain only low affinity isoenzymes of cyclic AMP phosphodiesterase (PDE; E.C.: 3.1.4.17), an intracellular regulator of cAMP. Starch gel electrophoresis showed that the isozyme of cAMP PDE of Leydig cells is masked in crude testis homogenates due to the relatively low level of these cells in the total population. In Leydig cells, there are two different electrophoretic forms expressed which resemble two of eleven different molecular forms of cAMP PDE demonstrated for comparison in 21 different organs of the adult rat.
An interstitial cell preparation from early juvenile testes, with a Leydig cell content of up to 20%, was also investigated electrophoretically with regard to molecular forms of cAMP PDE, the properties of which were characterized by kinetic analysis of cAMP hydrolysis. The results presented are discussed in relation to the onset of testosterone synthesis in Leydig cells of prepubertal rats leading to the initiation of male puberty. 相似文献
An interstitial cell preparation from early juvenile testes, with a Leydig cell content of up to 20%, was also investigated electrophoretically with regard to molecular forms of cAMP PDE, the properties of which were characterized by kinetic analysis of cAMP hydrolysis. The results presented are discussed in relation to the onset of testosterone synthesis in Leydig cells of prepubertal rats leading to the initiation of male puberty. 相似文献
355.
Minimal air in dogs 总被引:1,自引:0,他引:1
356.
C Poulos P Pasalimaniotou A Manolopoulou T Tsegenidis 《International journal of peptide and protein research》1991,38(4):308-313
Mixed carboxylic-phosphinic anhydrides derived from peptide acids and 1-oxo-1-chlorophospholane have been applied in the synthesis of the protected [Leu11]-SP by the fragment coupling strategy. The yields from fragment couplings were ca. 75%, the products were of high purity while the conditions of formation and coupling of the corresponding mixed phosphinic anhydrides, for optimum yields, have been evaluated. 相似文献
357.
358.
359.
Qing Jing Huiying Li Jianguo Fang Linda J. Roman Pavel Martásek Thomas L. Poulos Richard B. Silverman 《Bioorganic & medicinal chemistry》2013,21(17):5323-5331
In certain neurodegenerative diseases damaging levels of nitric oxide (NO) are produced by neuronal nitric oxide synthase (nNOS). It, therefore, is important to develop inhibitors selective for nNOS that do not interfere with other NOS isoforms, especially endothelial NOS (eNOS), which is critical for proper functioning of the cardiovascular system. While we have been successful in developing potent and isoform-selective inhibitors, such as lead compounds 1 and 2, the ease of synthesis and bioavailability have been problematic. Here we describe a new series of compounds including crystal structures of NOS-inhibitor complexes that integrate the advantages of easy synthesis and good biological properties compared to the lead compounds. These results provide the basis for additional structure–activity relationship (SAR) studies to guide further improvement of isozyme selective inhibitors. 相似文献
360.
Cytochrome P450 总被引:1,自引:0,他引:1
Since 1993, three new cytochrome P450 X-ray structures have been determined, giving a total of four known structures. Two of the new structures are in the substrate-free form and one is substrate-bound. These new structures, together with a wealth of mutagenesis studies on various P450s, have provided considerable information on what structural features control substrate specificity in P450s. In addition, some important insights into the catalytic mechanism have been made. 相似文献