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51.
Yazawa S Nishimura T Ide M Asao T Okamura A Tanaka S Takai I Yagihashi Y Saniabadi AR Kochibe N 《Glycobiology》2002,12(9):545-553
The accumulation of alpha1,2fucosylated antigens, such as Y (Fucalpha1,2Galbeta1,4 [Fucalpha1,3]GlcNAcbeta), Le(b) (Fucalpha1,2Galbeta1,3-[Fucalpha1,4]GlcNAcbeta), and H type 2 (Fucalpha1,2 Galbeta1,4GlcNAcbeta) occurs specifically within human colorectal tumor tissues and can be detected by an antifucosylated antigen antibody, such as the YB-2 antibody. In the present investigation, we found that the expression of these antigens bearing an alpha1,2-linked fucose correlated with the resistance of the tumor cells to anticancer treatments. Addition of an exogenous sugar acceptor for alpha1,2fucosyltransferase to the cell medium resulted in suppression of alpha1,2fucosylated antigen expression on the tumor cells and increased susceptibility to anticancer treatment. The increased susceptibility may be attributed to cancer cell-mediated priming by sugar acceptors for alpha1,2fucosyltransferase added to the medium. 相似文献
52.
Jan Klein Christophe Benoist Chella S. David Peter Demant Kirsten Fischer Lindahl Lorraine Flaherty Richard A. Flavell Ulrich Hämmerling Leroy E. Hood Stephen W. Hunt III Patricia P. Jones Philippe Kourilsky Hugh O. McDevitt Daniel Meruelo Donal B. Murphy Stanley G. Nathenson David H. Sachs Michael Steinmetz Susumu Tonegawa Edward K. Wakeland Elizabeth H. Weiss 《Immunogenetics》1990,32(3):147-149
53.
Susumu Miyata Yonezo Suzuki Seiichiro Kamisaka Yoshio Masuda 《Physiologia plantarum》1981,51(4):402-406
Indole-3-acetaldehyde oxidase was partially purified from the epicotyl of Pisum satiyum seedlings by column chromatography using CM-Sephadex and Sephadex G-150. The enzyme was only active in the presence of molecular oxygen. The activity was maximal at pH 8.0, and the Km value for indole-3-acetaldehyde was 1.4 × 10−3 M . The enzyme was inhibited strongly by p -hydroxymercuribenzoate, cyanide and hydroxylamine, suggesting that it contains sulfhydryl group(s) and a metal component such as iron. 相似文献
54.
A mutant hemolysin with lower biological activity produced by a mutant Vibrio parahaemolyticus 总被引:1,自引:0,他引:1
Takeshi Honda Yuxin Ni Schunkichi Hori Hikaru Takakura Susumu Tsunasawa Fumino Sakiyama Toshio Miwatani 《FEMS microbiology letters》1989,61(1-2):95-100
Abstract A mutant toxin (m-TDH) of thermostable direct hemolysin (Vp-TDH) of Vibrio parahaemolyticus w was isolated from the culture of a strain of this organism mutagenized with N -methyl- N '-nitro- N -nitrosoguanidine. Although the m-TDH had a molecular structure similar to the native Vp-TDH, the m-TDH retained only about 7% residual hemolytic activity of the native toxin. Furthermore, other biological activities of m-TDH, such as lethality in mice and enterotoxicity in rabbit ileal loops, were also weakened. The m-TDH was immunologically indistinguishable from the native Vp-TDH. These results suggest that the m-TDH is only slightly different in structure from the native Vp-TDH. Also, the mutagenized site in m-TDH, which is not immunogenic, seems to be involved in expressing not only hemolytic activity but also lethal and enterotoxic activity. 相似文献
55.
56.
Tohru Kobayashi Yasushi Kageyama Nobuyuki Sumitomo Katsuhisa Saeki Tsuyoshi Shirai Susumu Ito 《World journal of microbiology & biotechnology》2005,21(6-7):961-967
Summary Crystallographic analysis of the highly alkaline M-protease from an alkaliphilic Bacillus strain shows the occurrence of a unique salt bridge triad Arg19–Glu271–Arg275 (in subtilisin BPN′ numbering), which is not
found in less alkaline true subtilisins BPN′ and Carlsberg from Bacillus amyloliquefaciens and Bacillus licheniformis, respectively. Because the corresponding residues are all Gln residue in the subtilisin BPN′, Gln residue was engineered
into the position(s) 19, 271 and/or 275 in M-protease by site-directed mutagenesis. Disruptions of the salt bridge caused
the reduction of the thermostability of the mutant proteins at alkaline pH with the following decreasing order of thermal
inactivation rate; the wild-type > Arg275 → Gln > Glu271 → Gln > Arg19 → Gln/Glu271 → Gln/Arg275 → Gln > Arg19 → Gln. This
result provides the evidence that the salt bridge triad contributes to the thermostability and structural rigidity of the
highly alkaline M-protease. 相似文献
57.
Hatano N Ohya S Muraki K Clark RB Giles WR Imaizumi Y 《The Journal of biological chemistry》2004,279(7):5450-5459
Contributions of the C-terminal domain of Kv4.3 to the voltage-dependent gating of A-type K+ current (IA) were examined by (i) making mutations in this region, (ii) heterologous expression in HEK293 cells, and (iii) detailed voltage clamp analyses. Progressive deletions of the C terminus of rat Kv4.3M (to amino acid 429 from the N terminus) did not markedly change the inactivation time course of IA but shifted the voltage dependence of steady state inactivation in the negative direction to a maximum of -17 mV. Further deletions (to amino acid 420) shifted this parameter in the positive direction, suggesting a critical role for the domain 429-420 in the voltage-dependent regulation of IA. There are four positively charged amino acids in this domain: Lys423, Lys424, Arg426, and Arg429. The replacement of the two arginines with alanines (R2A) resulted in -23 and -13 mV shifts of inactivation and activation, respectively. Additional replacement of the two lysines with alanines did not result in further shifts. Single replacements of R426A or R429A induced -15 and -10 mV shifts of inactivation, respectively. R2A did not significantly change the inactivation rate but did markedly change the voltage dependence of recovery from inactivation. These two arginines are conserved in Kv4 subfamily, and alanine replacement of Arg429 and Arg432 in Kv4.2 gave essentially the same results. These effects of R2A were not modulated by co-expression of the K+ channel beta subunit, KChIPs. In conclusion, the two arginines in the cytosolic C-terminal domain of alpha-subunits of Kv4 subfamily strongly regulate the voltage dependence of channel activation, inactivation, and recovery. 相似文献
58.
59.
Development of novel carrier using natural zeolite and continuous ethanol fermentation with immobilized Saccharomyces cerevisiae in a bioreactor 总被引:1,自引:0,他引:1
Sho Shindo Susumu Takata Haruo Taguchi Noboru Yoshimura 《Biotechnology letters》2001,23(24):2001-2004
A natural zeolite, easily vitrified and blown at 1300 °C with a high porosity and diam. of 5–100 m, was used to immobilize Saccharomyces cerevisiae at 3.6 × 108 cells ml–1 carrier. When the abilities of natural zeolite carrier were compared with glass beads, the capacity for immobilization and alcohol fermentation activity were, respectively, 2-fold higher and 1.2-fold higher than that of glass beads. Continuous alcohol fermentation was stable for over 21 d without breakage of the carrier. 相似文献
60.
Setsu Nakae Shigeaki Ito Mariko Higa Takeshi Senoura Jun Wasaki Atsushi Hijikata Masafumi Shionyu Susumu Ito Tsuyoshi Shirai 《Journal of molecular biology》2013
The crystal structure of a novel component of the mannan biodegradation system, 4-O-β-d-mannosyl-d-glucose phosphorylase (MGP), was determined to a 1.68-Å resolution. The structure of the enzyme revealed a unique homohexameric structure, which was formed by using two helices attached to the N-terminus and C-terminus as a tab for sticking between subunits. The structures of MGP complexes with genuine substrates, 4-O-β-d-mannosyl-d-glucose and phosphate, and the product d-mannose-1-phosphate were also determined. The complex structures revealed that the invariant residue Asp131, which is supposed to be the general acid/base, did not exist close to the glycosidic Glc-O4 atom, which should be protonated in the catalytic reaction. Also, no solvent molecule that might mediate a proton transfer from Asp131 was observed in the substrate complex structure, suggesting that the catalytic mechanism of MGP is different from those of known disaccharide phosphorylases. 相似文献