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Suh YG Kim YH Park MH Choi YH Lee HK Moon JY Min KH Shin DY Jung JK Park OH Jeon RO Park HS Kang SA 《Bioorganic & medicinal chemistry letters》2001,11(4):559-562
The structure-activity relationship and molecular modelings of a novel pimarane COX-2 inhibitor are reported. Particularly, a series of linker extended analogues designed on the basis of these studies exhibited significantly enhanced COX-2 inhibitory activities and selectivities. 相似文献
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S-Methyl methanethiosufinate (1) and S-methyl 2-propene-1-thiosulfinate (2) were easily seperated from Chinese chive (Allium tuberosum L.) using simple column chromatography. Both compounds showed significant antibacterial activities against E. coli O-157:H7 including spoilage microorganism in food. Structural assignment was based on Mass and NMR-spectroscopic methods. 相似文献
146.
To emerge from the egg case, Argiope aurantia spiderlings must penetrate a tightly woven outer cover composed primarily of large-diameter cylindrical gland fibers and small-diameter fibers, likely of aciniform gland origin. They accomplish this using enzymatic digestion and mastication to form a communal hole in the outer cover. The involvement of proteolytic enzymes in this process was demonstrated by zymography of spiderling homogenates and washes made from the edges of holes. The specific source(s) of the proteases is unknown, but histological examination of spiderling sections indicates that the digestive tract, venom glands, and gnathocoxal glands are all functioning at the time of emergence from the egg case. Observations on edges of holes indicate that spiderlings are able to solubilize the small-diameter fibers completely, but cylindrical gland fibers only partially. In the outer cover, cylindrical fibers are composed of numerous fibrils embedded within a matrix. Spiderlings appear to be unable to solubilize the fibrils, but digestion of the matrix allows the spiderlings to push the fibrils aside to create the opening. 相似文献
147.
Lim YS So HS Kim MS Moon G Won JH Baek SW Moon SR Yang SH Kim BJ Ko CB Park R 《Life sciences》2002,70(20):2391-2401
The hypoglycemic drug, troglitazone (TGZ) has antioxidant activity. Superoxide dismutase (SOD) removes superoxide produced by cells. We measured the response of SOD-like activity (deltaSOD) to ascorbic acid (AA) or TGZ using electron spin resonance at various glucose concentrations in polymorphonuclear leukocytes from 18 type 2 diabetic patients and 18 healthy controls. In control and diabetic subjects, ASOD in response to AA was dose-dependent (maximal effect at 100 ng/ml). Maximal response occurred 2 min after AA addition (50 ng/ml). In cells from diabetic patients, ASOD with 25 ng/ml AA was significantly less than for healthy controls. The deltaSOD with AA changed little at glucose concentration from 0 to 200 mg/dl. In patient and control cells, higher glucose concentrations (400 to 800 mg/dl) reduced ASOD with AA. Response patterns with TGZ resembled those with AA. deltaSOD with AA correlated positively with glycosylated hemoglobin A1c. Conclusions: The present data suggest that an amerioration of blood glucose on high levels in diabetic patients plays an important role in an antioxidant efficacy of TGZ and AA on leukocytes in patients. 相似文献
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Choi JY Lee SH Park CY Heo WD Kim JC Kim MC Chung WS Moon BC Cheong YH Kim CY Yoo JH Koo JC Ok HM Chi SW Ryu SE Lee SY Lim CO Cho MJ 《The Journal of biological chemistry》2002,277(24):21630-21638
Plants express numerous calmodulin (CaM) isoforms that exhibit differential activation or inhibition of CaM-dependent enzymes in vitro; however, their specificities toward target enzyme/protein binding are uncertain. A random peptide library displaying a 22-mer peptide on a bacteriophage surface was constructed to screen peptides that specifically bind to plant CaM isoforms (soybean calmodulin (ScaM)-1 and SCaM-4 were used in this study) in a Ca2+-dependent manner. The deduced amino acid sequence analyses of the respective 80 phage clones that were independently isolated via affinity panning revealed that SCaM isoforms require distinct amino acid sequences for optimal binding. SCaM-1-binding peptides conform to a 1-5-10 ((FILVW)XXX(FILV) XXXX(FILVW)) motif (where X denotes any amino acid), whereas SCaM-4-binding peptide sequences conform to a 1-8-14 ((FILVW)XXXXXX(FAILVW)XXXXX(FILVW)) motif. These motifs are classified based on the positions of conserved hydrophobic residues. To examine their binding properties further, two representative peptides from each of the SCaM isoform-binding sequences were synthesized and analyzed via gel mobility shift assays, Trp fluorescent spectra analyses, and phosphodiesterase competitive inhibition experiments. The results of these studies suggest that SCaM isoforms possess different binding sequences for optimal target interaction, which therefore may provide a molecular basis for CaM isoform-specific function in plants. Furthermore, the isolated peptide sequences may serve not only as useful CaM-binding sequence references but also as potential reagents for studying CaM isoform-specific function in vivo. 相似文献
150.
Peptide mimotopes of pneumococcal capsular polysaccharide of 6B serotype: a peptide mimotope can bind to two unrelated antibodies 总被引:3,自引:0,他引:3
Shin JS Yu J Lin J Zhong L Bren KL Nahm MH 《Journal of immunology (Baltimore, Md. : 1950)》2002,168(12):6273-6278
Two groups of bacteriophage clones displaying the antigenic properties of serotype 6B pneumococcal capsular polysaccharide (PS) were obtained from different phage libraries expressing random heptameric peptides. One group, biopanned with a mouse mAb (Hyp6BM1), is comprised of 17 phage clones expressing 10 unique sequences of linear peptides. The other group, selected with another mAb (Hyp6BM8), contained six clones, all of which expressed the identical circular peptide. Phage clones expressing the linear peptides (e.g., PhaM1L3) bound only to Hyp6BM1, but not other 6B PS-specific mAb, and their binding could be inhibited with pneumococcal capsular type 6B PS only. In contrast, a phage clone expressing the circular peptide (PhaM8C1) cross-reacted with several other 6B PS-specific mAbs, and their binding could be inhibited with pneumococcal capsular PS of 6A and 6B serotypes. Two short peptides, PepM1L3 and PepM8C1, reflecting the peptide inserts of the corresponding phage clones, could inhibit the binding of the two clones to their respective mAb. Interestingly, the peptide insert in PhaM8C1 was identical to that in PhaB3C4, a previously reported mimotope of alpha(2-->8) polysialic acid, Neisseria meningitidis group B PS. Indeed, PhaM8C1 bound to HmenB3 (a meningococcal Ab), and their association could be inhibited with alpha(2-8) polysialic acid, but not with 6B PS. Conversely, alpha(2-8) polysialic acid could not inhibit the binding of PhaM8C1 to Hyp6BM8. The two-dimensional nuclear magnetic resonance studies indicate that PepM8C1 peptide can assume several conformations in solution. The ability of this peptide to assume multiple conformations might account for its ability to mimic more than one Ag type. 相似文献