首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   12篇
  免费   0篇
  2021年   1篇
  2017年   1篇
  2016年   1篇
  2014年   4篇
  2011年   2篇
  2007年   1篇
  2002年   1篇
  1999年   1篇
排序方式: 共有12条查询结果,搜索用时 15 毫秒
1.
The stoichiometric complex formed between bovine -trypsin and Momordica charantia, Linn. Cucurbitaceae trypsin inhibitor A (MCTI-A) was crystallized and its X-ray crystal structure was refined to a final R value of 0.179 using data of 7.0- to 1.8-Å resolution. Combination with results on the complex of MCTI-A with porcine trypsin gives the sequence of MCTI-A definitely, of which 13 residues are conserved compared with other squash family trypsin inhibitors. Its spatial structure and the conformation of its primary binding segment from Cys3I (P3) to Glu7I (P3), which contains a reactive scissile bond Arg5I C–Ile6I N, were found to be very similar to the other squash family proteinase inhibitors.  相似文献   
2.
The influence of various combinations of glycerol and lactose feed on the biosynthesis of two polyketide metabolites, lovastatin and (+)-geodin, by Aspergillus terreus ATCC20542 in a discontinuous fed-batch culture was presented. In these experiments lactose and/or glycerol were also used as the initial carbon substrates in the cultivation media. The application of glycerol feed, when lactose is the initial substrate, leads to the appreciable lovastatin concentration in the broth (122.4 mg l−1), nevertheless the abundant (+)-geodin level is at the same time obtained (255.5 mg l−1). The cultures with glycerol as the initial substrate and fed with lactose produce less lovastatin and (+)-geodin. The application of the various combined glycerol and/or lactose feeds allows for improving lovastatin production up to 161.8 mg l−1 and decreases (+)-geodin concentration to 98.7 mg l−1. The analysis of product formation rates and yield coefficients indicates that lovastatin is more efficiently produced on lactose, especially in the initial stages of the cultivation. Glycerol efficiently sustains fungal activity to form these polyketides in the late idiophase but it mainly favours (+)-geodin formation, if solely used in the feed. The feeds performed both with lactose and glycerol occur to be the most desired to maximise lovastatin and minimise (+)-geodin formation.  相似文献   
3.
Developing a rational strategy to control intracellular reactive oxygen species (ROS) requires understanding the mechanism of antioxidant activity. In this investigation the properties of a novel synthetic analog of vitamin E (IRFI005) with potent antioxidant activity are described. A mechanism is proposed for its efficient radical-scavenging effects. Cellular antioxidant and antitoxicity assays showed IRFI005 to freely permeate across cellular membranes, enabling it to be an effective suppressor of intracellular ROS and to protect cells against toxicity induced by free radical generating compounds. The free radical-scavenging activity of IRFI005 examined by UV–Vis and electron spin resonance (ESR) techniques clearly confirmed a “two electrons and/or H-atom” donation mechanism for each molecule of IRFI005. Reducing power assay as well as semi-empirical calculations revealed that under physiological conditions (pH∼7) almost all IRFI005 molecules are in the anionic state (IRFI005). Data indicated that the electron donating ability of IRFI005 was dominant at physiological pH because of higher stability of quinine-IRFI005 and less barrier energy of IRFI005 than neutral IRFI005. Consequently, the efficient cellular protection of IRFI005 against toxic free radicals can be explained by a two electron-transfer process, because of reduced inter-frontier molecular orbital energy gap barrier at physiological pH. Our findings suggest that hydrophilic vitamin E-like antioxidants are good candidates in designing novel therapeutic strategies for inhibition of oxidative stress associated with different human diseases.  相似文献   
4.
The insulin epitopes for two monoclonal antibodies (mAbs), OXI‐005 and HUI‐018, commonly used in combination for insulin concentration determination in sandwich assays, were determined using X‐ray crystallography. The crystal structure of the HUI‐018 Fab in complex with human insulin (HI) was determined and OXI‐005 Fab crystal structures were determined in complex with HI and porcine insulin (PI) as well as on its own. The OXI‐005 epitope comprises insulin residues 1,3,4,19–21 (A‐chain) and 25–30 (B‐chain) and for HUI‐018 residues 7,8,10–14,17 (A‐chain) and 5–7, 10, 14 (B‐chain). The areas of insulin involved in interactions with the mAb are 20% (OXI‐005) and 24% (HUI‐018) of the total insulin surface. Based on the Fab complex crystal structures with the insulins a molecular model for simultaneous binding of the Fabs to PI was built and this model was validated by small angle X‐ray scattering measurements for the ternary complex. The epitopes for the mAbs on insulin were found well separated from each other as expected from luminiscent oxygen channeling immunoassay results for different insulins (HI, PI, bovine insulin, DesB30 HI, insulin glargine, insulin lispro). The affinities of the OXI‐005 and HUI‐018 Fabs for HI, PI, and DesB30 HI were determined using surface plasmon resonance. The K Ds were found to be in the range of 1–4 nM for the HUI‐018 Fab, while more different for the OXI‐005 Fab (50 nM for HI, 20 nM for PI and 400 nM for DesB30 HI) supporting the importance of residue B30 for binding to OXI‐005.  相似文献   
5.
In the present study effect of asiaticoside, on healing of skin wounds in Cirrhinus mrigala is reported. Skin wound, approx. 2 mm in diameter was excised using sterile disposable biopsy punch. Immediately after infliction of the wound, epidermis from wound edge starts migrating as thin sheet toward wound gap. Fronts of migrating epidermis gradually advance, and results in complete epithelialization of wound. Experiments were conducted for 30 days and fishes were divided into control, sham, vehicle control and asiaticoside treated groups. Immunohistochemical localization of proliferating cell nuclear antigen positive cells indicating cellular proliferation and caspase 3 positive cells reflecting apoptosis was carried out and their density at different post wound intervals in each fish group was analyzed. Significant increase in cellular proliferation as well as decrease in apoptosis in both epidermis and dermis in fish treated with asiaticoside compared to sham and vehicle control fish is observed at different intervals of wound repair. This suggests that in treated group healing of skin wounds in fish is enhanced than in sham and vehicle control groups. Asiaticoside treatment in healing of skin wounds would greatly be beneficial to fish farmers as it could protect fish from invasion of pathogens and check fish mortality.  相似文献   
6.
7.
Shinkarev VP  Wraight CA 《FEBS letters》2007,581(8):1535-1541
The cytochrome bc(1) complex (commonly called Complex III) is the central enzyme of respiratory and photosynthetic electron transfer chains. X-ray structures have revealed the bc(1) complex to be a dimer, and show that the distance between low potential (b(L)) and high potential (b(H)) hemes, is similar to the distance between low potential hemes in different monomers. This suggests that electron transfer between monomers should occur at the level of the b(L) hemes. Here, we show that although the rate constant for b(L)-->b(L) electron transfer is substantial, it is slow compared to the forward rate from b(L) to b(H), and the intermonomer transfer only occurs after equilibration within the first monomer. The effective rate of intermonomer transfer is about 2-orders of magnitude slower than the direct intermonomer electron transfer.  相似文献   
8.
Parkinson׳s disease is the second most common neurodegenerative disorder. The exact cause of selective dopaminergic neurodegeneration is unknown, but it is supposed that etiology of Parkinson׳s disease is multifactorial and consists of an interaction between environmental factors and genetic predisposition. To find out the association between environmental factors and risk of Parkinson׳s disease, a case control study was designed including 97 Parkinson׳s disease patients and 97 controls. Logistic regression analysis was used to determine the risk factors for Parkinson׳s disease. Results from the present study showed that gender, religion, education, place of living, occupation, dietary habits, tobacco chewing, smoking, alcohol intake, and head injury had no association with PD. However, chemical exposure and well water drinking were significantly associated with PD, which concluded that environmental factors could act as a risk factor for PD in some way.  相似文献   
9.
Alzheimer׳s disease (AD) is one of the most common dementias showing slow progressive cognitive decline. Progression of intracerebral accumulation of beta amyloid (Aβ) peptides by the action of amyloid binding alcohol dehydrogenase (ABAD), a mitochondrial enzyme and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) and the degradation of Acetylcholinesterase (AChE) the main pathological characteristics of AD. Therefore, it is of interest to evaluate the importance of fisetin (a flavonol that belongs to the flavonoid group of polyphenols) binding with AChE, ABAD and BACE1 proteins. Docking experiment of fisetin with these proteins using two different tools namely iGEMDOCK and FlexX show significant binding with acceptable binding values. Thus, the potential inhibitory role of fisetin with AD associated proteins is documented.  相似文献   
10.
The most common characteristics of diverse age-related neurodegenerative diseases are aggregation and accumulation of the misfolded protein in the brain. Alzheimer׳s disease (AD) is one of these protein conformational diseases. Extracellular accumulation of amyloid β (Aβ) is one the neuropathological hallmarks of Alzheimer disease. Various studies have shown that mutation in specific hydrophobic region of Aβ protein inhibit the formation of β sheet, thus aggregation of this protein is stalled. The identification of such mutation in Aβ protein can help us in elucidating the etiology of sporadic Aβ. In our study we have selected three positions: 19ILU, 21ALA and 41ILU in Aβ protein based on their hydrophobic nature and substituted them with PRO ( βSheet breaker). The effects of the substitutions were analysed using molecular dynamics simulation studies. The results validated that the mutations in the specified regions change the hydrophobicity of the protein and the βsheet formation was declined to zero per cent.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号