排序方式: 共有96条查询结果,搜索用时 15 毫秒
41.
Yamakura F Matsumoto T Ikeda K Taka H Fujimura T Murayama K Watanabe E Tamaki M Imai T Takamori K 《Journal of biochemistry》2005,138(1):57-69
We reported previously that a single tryptophan residue, Trp32, in human Cu,Zn-superoxide dismutase is specifically modified by peroxynitrite-CO2 [Yamakura et al. (2001) Biochim. Biophys. Acta 1548, 38-46]. In this study, we modified Cu,Zn-superoxide dismutase by using a combination of myeloperoxidase, hydrogen peroxide, and nitrite. The modified enzyme showed no loss of copper and zinc, and 15% less enzymatic activity. Trp32 was the only significant amino acid lost. After trypsin digestion of the modified SOD with peroxynitrite-CO2 and the myeloperoxidase system, six newly appearing peptides containing tryptophan derivatives were observed on microLC-ESI-Q-TOF mass analyses and HPLC with a photodiode-array detector. The derivatives of the tryptophan residue exhibiting mass increases of 4, 16 (2 peaks), 32, 45 (major), and 45 Da (minor) were identified as kynurenine, oxindole-3-alanine and its derivatives, dihydroxytryptophan, 6-nitrotryptophan and 5-nitrotryptophan, respectively. We further identified 6-nitrotryptophan from the 1H-NMR spectrum for the pronase-digested product and calculated the yield of 6-nitrotryptophan as being about 30% for each of the modification methods. The tryptophan residue in the modified human Cu,Zn-superoxide dismutase gave the same spectra for the products including 6-nitrotryptophan as the major nitrated product with the two different modification systems. 相似文献
42.
Seko Y Fujimura T Taka H Mineki R Murayama K Nagai R 《Biochemical and biophysical research communications》2004,317(1):162-168
We previously reported that hypoxia followed by reoxygenation (hypoxia/reoxygenation) rapidly activated intracellular signaling such as mitogen-activated protein kinases (MAPKs) including extracellular signal-regulated protein kinase (ERK) 1/2, p38MAPK, and stress-activated protein kinases (SAPKs). To investigate the humoral factors which mediate cardiac response to hypoxia/reoxygenation, we analyzed the conditioned media from cardiac myocytes subjected to hypoxia/reoxygenation by two-dimensional electrophoresis and mass spectrometry. We identified cyclophilin A (CyPA) as one of the proteins secreted from cardiac myocytes in response to hypoxia/reoxygenation. Hypoxia/reoxygenation induced the expression of CyPA and its cell surface receptor CD147 on cardiac myocytes in vitro. This was also confirmed by ischemia/reperfusion in vivo. Recombinant human (rh) CyPA activated ERK1/2, p38MAPK, SAPKs, and Akt in cultured cardiac myocytes. Furthermore, CyPA significantly increased Bcl-2 in cardiac myocytes. These data strongly suggested that CyPA is released from cardiac myocytes in response to hypoxia/reoxygenation and may protect cardiac myocytes from oxidative stress-induced apoptosis. 相似文献
43.
Hernandez-Oliveira S Toyama MH Toyama DO Marangoni S Hyslop S Rodrigues-Simioni L 《The protein journal》2005,24(4):233-242
A new PLA2 (F16) was purified from Crotalus durissus terrificus venom by molecular exclusion chromatography followed by analytical reverse phase HPLC. The PLA2 (14.86 kDa by MALDI-TOF mass spectrometry) had an amino acid sequence of SLLQFNKMIKFETRKNAVPFYAFYGCYCGWGGRRRPKDATDRCCFVHDCCYEKVTKCNTKWDIYRYSLKSGYITCGKGTWCKEQICECDRVAAECLRRSLSTYKNGYMFYPDSRCRGPSETC,
and showed highly conserved Ca2+-binding and catalytic sites. F16 showed allosteric behavior with 10 mM Ca2+ and had temperature and pH optima of 25°C and 7.9, respectively. F16 (10 μg/ml) produced neuromuscular blockade in chick
biventer cervicis preparations in the absence and presence of crotapotin, indicating that crotapotin was not essential for
neuromuscular action in this preparation. In contrast, in mouse phrenic nerve-diaphragm preparations, the neuromuscular blockade
produced by the same concentration of toxin was dependent on crotapotin. Pre-incubation with heparin markedly reduced the
neurotoxicity of F16. These results show that the biochemical and structural properties of F16 are similar to those of the
PLA2 isoforms F15 and F17, but that the neurotoxicity and the requirement for crotapotin to form the crotoxin complex varies
according to the neuromuscular preparation. 相似文献
44.
Ryoji?NagaiEmail authorView authors OrcID profile Jun-ichi?Shirakawa Rei-ichi?Ohno Kota?Hatano Hikari?Sugawa Shoutaro?Arakawa Kenta?Ichimaru Shoh?Kinoshita Noriyuki?Sakata Mime?Nagai 《Glycoconjugate journal》2016,33(4):545-552
Advanced glycation end-products (AGEs) of the Maillard reaction were originally measured according to their fluorescent and browning properties. A subsequent study with instrumental analyses such as high-performance liquid chromatography and gas chromatography mass spectrometry more clearly demonstrated the involvement of each AGE structure in pathological conditions. Furthermore, immunochemical methods have also been developed to clarify the localization of AGEs in tissues and measurement of AGEs in multiple clinical samples. Although the involvement of AGEs in age-related diseases has progressed due to immunochemical techniques, the relationship between AGE structure and diseases has not been clear because little was known about the epitope structure of each anti-AGE antibody. However, the development of epitope-identified antibodies against AGEs has made it possible to clarify AGE structures involved in diseases. This review discusses not only the usability of anti-AGE antibodies to evaluate AGEs and disease pathology and screen AGE inhibitors, but also describes their usage. 相似文献
45.
Eriko Yamamoto Toyoyoshi Uchida Hiroko Abe Hikari Taka Tsutomu Fujimura Koji Komiya Akemi Hara Takeshi Ogihara Yoshio Fujitani Takashi Ueno Satoru Takeda Hirotaka Watada 《Biochemical and biophysical research communications》2014
Autophagy is a tightly regulated self-digestion system. As in other cell types, autophagy plays an essential role in the homeostasis of pancreatic beta cells. However, the mechanisms involved in the deterioration of beta cell function caused by autophagic failure have not yet been fully elucidated. To gain insight into its mechanisms, we compared the protein expression of islets from beta cell-specific Atg7-deficient mice (Atg7Δβ-cell mice) and their controls (Atg7f/f mice). Liquid chromatography/mass spectrometry after 1-dimensional electrophoresis identified the increased expression of ERp57/GRP58 in islets isolated from Atg7Δβ-cell mice compared with those from Atg7f/f mice. The expression level of ERp57 was also elevated in rat insulinoma INS-1 cells by inducible knock-down of the atg7-gene. In Atg7 knock-down INS-1 cells, the suppression of ERp57 expression by siRNA resulted in an increase in the level of cleaved Caspase-3 protein and a decrease in the number of live cells. Furthermore, cell cycle analyses demonstrated that the suppressed expression of ERp57 increased the sub-G1 population. These data reveal that increased expression of ERp57 may contribute to the protection from beta cell death caused by autophagic failure. 相似文献
46.
Japanese macaques form a cross-modal representation of their own species in their first year of life
Adachi I Kuwahata H Fujita K Tomonaga M Matsuzawa T 《Primates; journal of primatology》2006,47(4):350-354
We tested whether infant Japanese macaques (Macaca fuscata) have a cross-modal representation of their own species. We presented monkeys with a photograph of either a monkey or a human face on an LCD monitor after playing back a vocalization of one of those two species. The subjects looked at the monitor longer when a human face was presented after the monkey vocalization than when the same face was presented after human vocalization. This suggests that monkeys recall and expect a monkey’s face upon hearing a monkey’s voice. 相似文献
47.
Priya Joyce Melissa Kuwahata Nicole Turner Prakash Lakshmanan 《Plant cell reports》2010,29(2):173-183
A reproducible method for transformation of sugarcane using various strains of Agrobacterium tumefaciens (A. tumefaciens) (AGL0, AGL1, EHA105 and LBA4404) has been developed. The selection system and co-cultivation medium were the most important
factors determining the success of transformation and transgenic plant regeneration. Plant regeneration at a frequency of
0.8–4.8% occurred only when callus was transformed with A. tumefaciens carrying a newly constructed superbinary plasmid containing neomycin phosphotransferase (nptII) and β-glucuronidase (gusA) genes, both driven by the maize ubiquitin (ubi-1) promoter. Regeneration was successful in plants carrying the nptII gene but not the hygromycin phosphotransferase (hph) gene. NptII gene selection was imposed at a concentration of 150 mg/l paromomycin sulphate and applied either immediately or 4 days after
the co-cultivation period. Co-cultivation on Murashige and Skoog (MS)-based medium for a period of 4 days produced the highest
number of transgenic plants. Over 200 independent transgenic lines were created using this protocol. Regenerated plants appeared
phenotypically normal and contained both gusA and nptII genes. Southern blot analysis revealed 1–3 transgene insertion events that were randomly integrated in the majority of the
plants produced. 相似文献
48.
49.
Yoshida H Tomita H Sugano E Isago H Ishiguro S Tamai M 《Cell structure and function》2008,33(1):21-26
To investigate the effect of brain derived neurotrophic factor (BDNF) on the phagocytic activity in iris pigment epithelial (IPE) cells, purified porcine photoreceptor outer segments (POS) were applied to cultured IPE cells for three hours. To measure phagocytic activities, bound and total POS were differentially stained using a double immunofluorescence staining method. BDNF increased the binding of POS in IPE cells in a dose-dependent manner. Ingestion of POS, however, was not affected throughout the concentrations used in this study. To investigate the signal transduction pathways of BDNF, a phosphatidylinositol 3-kinase (PI3K) inhibitor, LY294002, and MAPK/ERK kinase (MEK) inhibitor, PD98059, were used for this study. LY294002 had no effect on the binding and ingestion of POS in BDNF-treated IPE cells. On the other hand, PD98059 completely inhibited the increase of POS binding in BDNF-treated cells and also decreased the ingestion of POS. These results indicate that increased POS binding activity by BDNF and the decreased ingestion of POS were mediated through the MAPK pathway. 相似文献
50.
Growth-related renal type II Na/Pi cotransporter 总被引:11,自引:0,他引:11
Segawa H Kaneko I Takahashi A Kuwahata M Ito M Ohkido I Tatsumi S Miyamoto K 《The Journal of biological chemistry》2002,277(22):19665-19672