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排序方式: 共有288条查询结果,搜索用时 15 毫秒
1.
2.
A milk protein, occurring in the whey fraction, has been characterized from camel milk. Determination of the primary structure reveals the existence of two related types of chain with residue differences in at least the N-terminal region. A fragment representing an N-terminal part of the protein was also recovered (heterogeneous at the same positions). The absence of cysteine residues in the protein shows that no disulphide bridges are present. The pattern of fragments and a parent protein resembles that for casein and its fragments, showing that fragments and a multiplicity of forms may be typical for different milk proteins. 相似文献
3.
Alia Islam Obaid Ullah Beg Bengt Persson Zafar H. Zaidi Hans Jörnvall 《The protein journal》1988,7(5):561-569
The structure of the hernoglobin α-chain of Rose-ringed Parakeet was determined by sequence degradations of the intact subunit, the CNBr fragments, and peptides obtained by digestion with staphylococcal Glu-specific protease and trypsin. Using this analysis, the complete α-chain structure of 21 avian species is known, permitting comparisons of the protein structure and of avian relationships. The structure exhibits differences from previously established avian α-chains at a total of 61 positions, five of which have residues unique to those of the parakeet (Ser-12, Gly-65, Ser-67, Ala-121, and Leu-134). The analysis defines hemoglobin variation within an additional avian order (Psittaciformes), demonstrates distant patterns for evaluation of relationships within other avian orders, and lends support to taxonomic conclusions from molecular data. 相似文献
4.
Induction of NF-kappa B DNA-binding activity during the G0-to-G1 transition in mouse fibroblasts. 总被引:1,自引:0,他引:1 下载免费PDF全文
A S Baldwin Jr J C Azizkhan D E Jensen A A Beg L R Coodly 《Molecular and cellular biology》1991,11(10):4943-4951
A DNA-binding factor with properties of NF-kappa B and another similar activity are rapidly induced when growth-arrested BALB/c 3T3 cells are stimulated with serum growth factors. Induction of these DNA-binding activities is not inhibited by pretreatment of quiescent cells with the protein synthesis inhibitor cycloheximide. Interestingly, the major NF-kappa B-like activity is not detected in nuclear extracts of proliferating cells, and thus its expression appears to be limited to the G0-to-G1 transition in 3T3 cells. These DNA-binding activities bind many of the expected NF-kappa B target sequences, including elements in the class I major histocompatibility complex and human immunodeficiency virus enhancers, as well as a recently identified NF-kappa B binding site upstream of the c-myc gene. Furthermore, both the class I major histocompatibility complex and c-myc NF-kappa B binding sites confer inducibility on a minimal promoter in 3T3 cells stimulated with serum growth factors. The results demonstrate that NF-kappa B-like activities are immediate-early response proteins in 3T3 cells and suggest a role for these factors in the G0-to-G1 transition. 相似文献
5.
6.
Obaid Ullah Beg Hedvig von Bahr-Lindström Zafar H. Zaidi Hans Jörnvall 《Bioscience reports》1984,4(12):1065-1070
A small protein (Mr about 14 000) rich in cysteine/half-cystine has been isolated from camel milk by exclusion chromatography and reverse-phase high-performance liquid chromatography. The N-terminal amino acid sequence shows a region with several positional identities with and -caseins, which however lack cysteine residues; postions 16–20 are identical and involve the serine residues that have been found to be phosphorylated in -caseins. 相似文献
7.
Proteolytic enzymes are ubiquitous in occurrence, being found in all living organisms, and are essential for cell growth and differentiation. The extracellular proteases are of commercial value and find multiple applications in various industrial sectors. Although there are many microbial sources available for producing proteases, only a few are recognized as commercial producers. A good number of bacterial alkaline proteases are commercially available, such as subtilisin Carlsberg, subtilisin BPN' and Savinase, with their major application as detergent enzymes. However, mutations have led to newer protease preparations with improved catalytic efficiency and better stability towards temperature, oxidizing agents and changing wash conditions. Many newer preparations, such as Durazym, Maxapem and Purafect, have been produced, using techniques of site-directed mutagenesis and/or random mutagenesis. Directed evolution has also paved the way to a great variety of subtilisin variants with better specificities and stability. Molecular imprinting through conditional lyophilization is coming up to match molecular approaches in protein engineering. There are many possibilities for modifying biocatalysts through molecular approaches. However, the search for microbial sources of novel alkaline proteases in natural diversity through the "metagenome" approach is targeting a hitherto undiscovered wealth of molecular diversity. This fascinating development will allow the biotechnological exploitation of uncultured microorganisms, which by far outnumber the species accessible by cultivation, regardless of the habitat. In this review, we discuss the types and sources of proteases, protease yield-improvement methods, the use of new methods for developing novel proteases and applications of alkaline proteases in industrial sectors, with an overview on the use of alkaline proteases in the detergent industry. 相似文献
8.
Amino acid sequence surrounding the lipoic acid cofactor of bovine kidney 2-oxoglutarate dehydrogenase complex 总被引:4,自引:0,他引:4
The 2-oxoglutarate dehydrogenase complex was succinylated using 2-oxo[5-14C]glutarate in the presence of N-ethylmaleimide to label the lipoic acid cofactor of the transuccinylase (E2) component. Following peptic digestion, 14C-lipoate-containing peptides were purified and subjected to automated Edman degradation and amino acid analysis. The amino acid sequence surrounding the lipoyllysine residue is reported. 相似文献
9.
Afsheen Raza Najia K. Ghanchi Ali bin Sarwar Zubairi Ahmed Raheem Sobia Nizami Mohammad Asim Beg 《PloS one》2013,8(12)
Background
Cytokine-mediated endothelial activation pathway is a known mechanism of pathogenesis employed by Plasmodium falciparum to induce severe disease symptoms in human host. Though considered benign, complicated cases of Plasmodium vivax are being reported worldwide and from Pakistan. It has been hypothesized that P.vivax utilizes similar mechanism of pathogenesis, as that of P.falciparum for manifestations of severe malaria. Therefore, the main objective of this study was to characterize the role of cytokines and endothelial activation markers in complicated Plasmodium vivax isolates from Pakistan.Methods and Principle Findings
A case control study using plasma samples from well-characterized groups suffering from P.vivax infection including uncomplicated cases (n=100), complicated cases (n=82) and healthy controls (n=100) were investigated. Base line levels of Tumor necrosis factor-α (TNF-α), Interleukin-6 (IL-6), Interleukin-10 (IL-10), Intercellular adhesion molecule-1 (ICAM-1), Vascular adhesion molecule-1(VCAM-1) and E-selectin were measured by ELISA. Correlation of cytokines and endothelial activation markers was done using Spearman’s correlation analysis. Furthermore, significance of these biomarkers as indicators of disease severity was also analyzed. The results showed that TNF-α, IL-10, ICAM-1and VCAM-1 were 3-fold, 3.7 fold and 2 fold increased between uncomplicated and complicated cases. Comparison of healthy controls with uncomplicated cases showed no significant difference in TNF-α concentrations while IL-6, IL-10, ICAM-1, VCAM-1 and E-selectin were found to be elevated respectively. In addition, significant positive correlation was observed between TNF-α and IL-10/ ICAM-1, IL-6 and IL-10, ICAM-1 and VCAM-1.A Receiver operating curve (ROC) was generated which showed that TNF-α, IL-10, ICAM-1 and VCAM-1 were the best individual predictors of complicated P.vivax malaria.Conclusion
The results suggest that though endothelial adhesion molecules are inducible by pro-inflammatory cytokine TNF-α, however, cytokine-mediated endothelial activation pathway is not clearly demonstrated as a mechanism of pathogenesis in complicated P.vivax malaria cases from Pakistan. 相似文献10.
Potential energy (PE) curves for intramolecular proton transfer in the ground (GSIPT) and intramolecular proton transfer in the excited (ESIPT) states of 3-hydroxychromone (3HC) have been studied using DFT-B3LYP/6-31G(d,p) and TD-DFT/6-31G(d,p) level of theory, respectively. Our calculations suggest the non-viability of GSIPT in 3HC. Excited states PE calculations show the existence of ESIPT process in 3HC. ESIPT in 3HC has also been explained in terms of HOMO and LUMO electron densities of the enol and keto tautomers of 3HC. 相似文献