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1.
Enzyme-enzyme interactions and control analysis. 2. The case of non-independence: heterologous associations 总被引:4,自引:0,他引:4
The association of different enzymes into a complex may induce changes in the kinetic parameters of its component enzymes. This implies that they cannot be treated as independent catalysts. It will affect the formulations and theorems of control analysis and necessitates the introduction of additional elasticities reflecting the effect of one enzyme on the rate of another. We show how this is achieved as an extension of the classical treatment. We present modified summation and connectivity theorems incorporating both homologous and heterologous interactions. The case of channelling of metabolites in such complexes is considered and an experimental method for its detection is suggested. 相似文献
2.
Luigi Ornano Alessandro Venditti Mauro Ballero Cinzia Sanna Luana Quassinti Massimo Bramucci Giulio Lupidi Fabrizio Papa Sauro Vittori Filippo Maggi Armanodoriano Bianco 《化学与生物多样性》2013,10(8):1464-1474
The essential oils of Artemisia arborescens growing in Sardinia (Italy), collected during three plant growth stages, i.e., from the vegetative stage to post‐blooming time, were characterized. Moreover, the in vitro antiproliferative and antioxidant activities of the oil isolated from aerial parts collected in February were evaluated. The essential oils belonged to the β‐thujone/chamazulene chemotype, notably with the highest amount of chamazulene (ca. 52%) ever detected up to now in the genus Artemisia and, in general, in essential oils. Quantitative variations in the oil composition were observed as the plant passes from the vegetative to the blooming stage. The oil was tested for its potential tumor cell growth‐inhibitory effect on T98G, MDA‐MB 435S, A375, and HCT116 human cell lines, using the MTT (=3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide) assay. The highest activity was observed on A375 and HCT116 cell lines, with IC50 values of 14 μg/ml. Moreover, the in vitro antioxidant and free radical‐scavenging assays revealed the oil to be an effective scavenger of the ABTS radical cation, with an activity comparable to that of Trolox®. These results support the use of A. arborescens oil for the treatment of inflamed skin conditions. Finally, the composition of the polar fraction of the A. arborescens aerial parts was also examined, and the main component detected was 5‐O‐caffeoylquinic acid, which was identified for the first time in this plant. 相似文献
3.
4.
Large scale genomic studies are generating significant amounts of data on the structure of cellular networks. This is in contrast to kinetic data, which is frequently absent, unreliable or fragmentary. There is, therefore, a desire by many in the community to investigate the potential rewards of analyzing the more readily available topological data. This brief review is concerned with a particular property of biological networks, namely structural conservations (e.g. moiety conserved cycles). There has been much discussion in the literature on these cycles but a review on the computational issues related to conserved cycles has been missing. This review is concerned with the detection and characterization of conservation relations in arbitrary networks and related issues, which impinge on simulation simulation software writers. This review will not address flux balance constraints or small-world type analyses in any significant detail. 相似文献
5.
A sensitivity analysis of general stoichiometric networks is considered. The results are presented as a generalization of Metabolic Control Analysis, which has been concerned primarily with system sensitivities at steady state. An expression for time-varying sensitivity coefficients is given and the Summation and Connectivity Theorems are generalized. The results are compared to previous treatments. The analysis is accompanied by a discussion of the computation of the sensitivity coefficients and an application to a model of phototransduction. 相似文献
6.
Costanzi S Lambertucci C Volpini R Vittori S Lupidi G Cristalli G 《Nucleosides, nucleotides & nucleic acids》2001,20(4-7):1037-1041
2,6-Dichloro-1-deazapurine and 2,6-dichloro-3-deazapurine were coupled with 1,2-O-diacetyl-5-O-benzoyl-3-deoxy-beta-D-ribofuranose. Deprotection of the obtained compounds and reaction with liquid ammonia gave the desired 2-chloroadenine nucleosides, which were dechlorinated to afford the corresponding 1-deaza and 3-deazaadenosine derivatives. Biological studies performed on ADA from calf intestine showed that these new nucleosides are inhibitors of the enzyme. 相似文献
7.
Sauro HM Hucka M Finney A Wellock C Bolouri H Doyle J Kitano H 《Omics : a journal of integrative biology》2003,7(4):355-372
Researchers in quantitative systems biology make use of a large number of different software packages for modelling, analysis, visualization, and general data manipulation. In this paper, we describe the Systems Biology Workbench (SBW), a software framework that allows heterogeneous application components--written in diverse programming languages and running on different platforms--to communicate and use each others' capabilities via a fast binary encoded-message system. Our goal was to create a simple, high performance, opensource software infrastructure which is easy to implement and understand. SBW enables applications (potentially running on separate, distributed computers) to communicate via a simple network protocol. The interfaces to the system are encapsulated in client-side libraries that we provide for different programming languages. We describe in this paper the SBW architecture, a selection of current modules, including Jarnac, JDesigner, and SBWMeta-tool, and the close integration of SBW into BioSPICE, which enables both frameworks to share tools and compliment and strengthen each others capabilities. 相似文献
8.
The stimulatory effects of adenosine analogues on a nuclear pool of protein kinase C (PKC) were examined using isolated rat splenocyte nuclei. Nuclear receptors met pharmacological criteria of A1 adenosine receptors including a potency profile in which cyclopentyladenosine (CPA), a selective A1 agonist, was more potent than 2-phenylaminoadenosine (2PAA), a selective A2 agonist. The selective A1 receptor agonist N6-1-(phenyl-2R-propyl) adenosine (R-PIA) activated PKC whereas the S diastereomer did not. The adenosine-induced PKC response could be attenuated using a monoclonal antibody to PKC, an A1 receptor antagonist, three known PKC inhibitors and pertussis toxin (PTX). The results suggest that adenosine may exert immunomodulatory effects through the activation of nuclear PKC. 相似文献
9.
Lucia Monti Donatella Donati Elisabetta Menci Samuele Cioni Matteo Bellini Irene Grazzini Sara Leonini Paolo Galluzzi Sauro Severi Luca Burroni Alfredo Casasco Lucia Morbidelli Emiliano Santarnecchi Pietro Piu 《PloS one》2015,10(2)
Literature has suggested that changes in brain flow circulation occur in patients with multiple sclerosis. In this study, digital subtraction angiography (DSA) was used to measure the absolute CCT value in MS patients and to correlate its value to age at disease onset and duration, and to expand disability status scale (EDSS). DSA assessment was performed on eighty MS patients and on a control group of forty-four age-matched patients. CCT in MS and control groups was calculated by analyzing the angiographic images. Lesion and brain volumes were calculated in a representative group of MS patients. Statistical correlations among CCT and disease duration, age at disease onset, lesion load, brain volumes and EDSS were considered. A significant difference between CCT in MS patients (mean = 4.9s; sd = 1.27s) and control group (mean = 2.8s; sd = 0.51s) was demonstrated. No significant statistical correlation was found between CCT and the other parameters in all MS patients. Significantly increased CCT value in MS patients suggests the presence of microvascular dysfunctions, which do not depend on clinical and MRI findings. Hemodynamic changes may not be exclusively the result of a late chronic inflammatory process. 相似文献
10.
Jacqueline Y. Quinn Robert Sidney Cox III Aaron Adler Jacob Beal Swapnil Bhatia Yizhi Cai Joanna Chen Kevin Clancy Michal Galdzicki Nathan J. Hillson Nicolas Le Novère Akshay J. Maheshwari James Alastair McLaughlin Chris J. Myers Umesh P Matthew Pocock Cesar Rodriguez Larisa Soldatova Guy-Bart V. Stan Neil Swainston Anil Wipat Herbert M. Sauro 《PLoS biology》2015,13(12)
Synthetic Biology Open Language (SBOL) Visual is a graphical standard for genetic engineering. It consists of symbols representing DNA subsequences, including regulatory elements and DNA assembly features. These symbols can be used to draw illustrations for communication and instruction, and as image assets for computer-aided design. SBOL Visual is a community standard, freely available for personal, academic, and commercial use (Creative Commons CC0 license). We provide prototypical symbol images that have been used in scientific publications and software tools. We encourage users to use and modify them freely, and to join the SBOL Visual community: http://www.sbolstandard.org/visual. 相似文献