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941.
942.
943.
Yagi M Narita K Maruyama S Sone K Kuwabara T Shimizu K 《Biochimica et biophysica acta》2007,1767(6):660-665
Adsorption of [(OH(2))(terpy)Mn(mu-O)(2)Mn(terpy)(OH(2))](3+) (terpy=2,2':6',2"-terpyridine) (1) onto montmorillonite K10 (MK10) yielded catalytic dioxygen (O(2)) evolution from water using a Ce(IV) oxidant. The Mn K-edge X-ray absorption near edge structure (XANES) of the 1/MK10 hybrid suggested that the oxidation state of the di-mu-oxo Mn(2) core could be Mn(III)-Mn(IV). However the pre-edge peak in the XANES spectrum of 1 adsorbed on MK10 is different from the neat 1 powder. The kinetic analysis of O(2) evolution showed that the catalysis requires cooperation of two equivalents of 1 adsorbed on MK10. The reaction of the [(bpy)(2)Mn(mu-O)(2)Mn(bpy)(2)](3+) (bpy=2,2'-bipyridine) (2)/MK10 hybrid with a Ce(IV) oxidant evolved O(2). However, the turnover number value was less than unity for 2/MK10, showing that 2 adsorbed on MK10 does not work as a catalyst. The terminal water ligands could be an important for the catalysis by adsorbed 1. The mechanism of O(2) production by photosynthetic oxygen evolving complex is discussed based on catalytic O(2) evolution by 1 adsorbed on MK10. 相似文献
944.
Hashimoto K Morishige K Sawada K Tahara M Shimizu S Ogata S Sakata M Tasaka K Kimura T 《Biochemical and biophysical research communications》2007,354(2):478-484
We previously reported that alendronate inhibits intraperitoneal dissemination in an in vivo ovarian cancer model. Recently, nitrogen-containing bisphosphonates have been reported to have antiangiogenic activities. In this study, alendronate inhibited human umbilical vein endothelial cell (HUVEC) migration and capillary-like structure formation in vitro. These inhibitory effects were associated with reduced Rho activation and suppression of the formation of actin stress fibers and focal adhesions in HUVECs. Furthermore, the inhibition by alendronate was reversed by geranylgeraniol, which abrogated the inhibition of Rho geranylgeranylation. Next, we examined the effect of alendronate on angiogenesis in disseminated ovarian tumors of athymic immunodeficient mice. Alendronate treatment reduced the intra-tumor neoangiogenesis compared with that in the non-treated mice, although tumor-derived VEGF expression was not altered. In conclusion, the in vivo anti-tumor effect of alendronate might be derived, at least in part, from its direct antiangiogenic effects on intra-tumor endothelial cells by inhibiting Rho geranylgeranylation. 相似文献
945.
Liu C Matsushita Y Shimizu K Makimura K Hasumi K 《Biochemical and biophysical research communications》2007,358(1):356-362
Two novel subtilisin-like serine proteases (AS-E1 and -E2) that activate prothrombin have been identified in a culture of the fungus Acremonium sp. The enzymes were purified through repeated hydrophobic interaction chromatography. The N-terminal sequences of AS-E1 (34.4 kDa) and AS-E2 (32 kDa) showed high similarity to the internal sequences of two distinct subtilisin-like hypothetical proteins from Chaetomium globosum. Both enzymes proteolytically activated prothrombin to meizothrombin(desF1)-like molecules, while the activation cleavage seemed to occur at a site (Tyr(316)-Ile(317)) that is four residues proximal to the canonical Xa cleavage site (Arg(320)-Ile(321)). Both enzymes inhibited plasma clotting, possibly due to extensive degradation of fibrinogen and production of meizothrombin(desF1)-like molecule. 相似文献
946.
947.
Kawai T Yokoyama Y Nagino M Kitagawa T Nimura Y 《Biochemical and biophysical research communications》2007,352(2):311-316
The effects of renal dysfunction on liver regeneration capacity have not been fully elucidated before, although many patients with renal failure are subjected to hepatectomy due to hepatobiliary diseases. In this study, we sought to determine the effects of renal dysfunction on the hepatic regeneration capacity using rat chronic renal failure model. After establishing chronic renal failure (CRF group) by semi-total renal resection, the rats were subjected to 70% partial hepatectomy (PHx). Rats without renal failure were used as control (Sham group). The hepatic regeneration rate, histology of the liver, clearance of indocyanine green into the bile, and the expression of hepatic regeneration-associated genes in the liver were evaluated. The hepatic regeneration rate was lower in CRF group as compared to Sham group on day 1 after PHx. Mitotic index evaluated by histologic examination on day 1 after PHx was also significantly lower in CRF group. However, no difference in these indices was observed on day 2 and 7 between Sham and CRF. Indocyanine green clearance rate was almost identical between Sham and CRF on day 7 following PHx. The baseline expressions of the hepatic regeneration-associated genes, such as IL-6, TNF-alpha, HGF, c-fos, and c-jun, in the liver of CRF were significantly lower than those of Sham. However, the rate of upregulation of these genes was not significantly different between Sham and CRF. These results clearly demonstrate that the renal dysfunction, although initially delays the onset, does not suppress the total hepatic regeneration capacity following partial hepatectomy. The function of the regenerated liver on day 7 after PHx also was not different. Our results provide a possibility that the hepatectomy can be indicated even for the patient with a chronic renal failure. 相似文献
948.
Okada S Ohshima K Uehara Y Shimizu H Hashimoto K Yamada M Mori M 《Biochemical and biophysical research communications》2007,356(1):102-106
Previously we identified an unusual potential dual Akt/protein kinase B consensus phosphorylation motif in the protein Synip (RxKxRS(97)xS(99)) with serine 99 as a unique Akt2, but not Akt1 or for Akt3, substrate phosphorylation site. Although we have previously reported that serine 99 to phenylalanine (S99F-Synip) resulted in a constitutive inhibition of insulin-stimulated Glut4 translocation, a recent report indicated that Synip serine 99 to alanine mutant (S99A-Synip) failed to inhibit insulin-stimulated Glut4 translocation [H. Sano, S. Kane, E. Sano, G.E. Lienhard, Synip phosphorylation does not regulate insulin-stimulated GLUT4 translocation, Biochem. Biophys. Res. Commun. 332 (2005) 880-884]. To address this apparent discrepancy, we have now examined the S99A-Synip mutant and find that this mutant behaves essentially identical to S99F-Synip in that overexpression inhibits insulin-stimulated Glut4 translocation and is incapable of undergoing insulin-stimulated Syntaxin4 dissociation. These data are consistent with Synip serine 99 phosphorylation required for insulin-stimulated Glut4 translocation. 相似文献
949.
Nocardia fusca and Nocardia pseudosporangifera produced (R)-3-pentyn-2-ol and (S)-3-pentyn-2-ol in 24 and 72 h reaction, respectively, from (RS)-3-pentyn-2-ol, with greater than 70% molar yields through a stereoinversion reaction involving stereoselective oxidation and reduction with 3-pentyn-2-one as an intermediate. 相似文献
950.
K Matsumura F Saito H Yamada A Hase Y Sunada T Shimizu 《Cellular and molecular biology, including cyto-enzymology》1999,45(6):751-762
In striated muscle, the cytoskeletal protein dystrophin, the protein product of the Duchenne muscular dystrophy gene, is associated with a number of sarcolemmal glycoproteins to form a large oligomeric complex, the dystrophin-glycoprotein complex (DGC). Over the last 10 years, four of these sarcolemmal glycoproteins, alpha-, beta-, gamma- and delta-sarcoglycans, have been shown to form a distinct subcomplex, the sarcoglycan complex, in the DGC. Furthermore, the genetic defects of alpha-, beta-, gamma- and delta-sarcoglycans have been identified as the causes of four distinct forms of muscular dystrophies, which are now collectively called sarcoglycanopathy. Current studies are beginning to focus on the biological functions of the sarcoglycan complex and the molecular mechanism by which its dysfunction leads to muscle cell degeneration. 相似文献