Limited proteolysis in porous membrane reactors containing immobilized trypsin

The Analyst ◽  
2017 ◽  
Vol 142 (14) ◽  
pp. 2578-2586 ◽  
Author(s):  
Jinlan Dong ◽  
Wenjing Ning ◽  
Weijing Liu ◽  
Merlin L. Bruening
Keyword(s):  
Protein Structures ◽  
Limited Proteolysis ◽  
Porous Membrane ◽  
Membrane Reactors ◽  
Immobilized Trypsin ◽  
Limited Digestion

Trypsin-containing membranes effect limited digestion to identify facile digestion sites in protein structures.

scholarly journals Modeling of ethylbenzene dehydrogenation in catalytic membrane reactor with porous membrane

2014 ◽  
Vol 2 (1) ◽  
pp. 1-9 ◽  
Author(s):  
E.V. Shelepova ◽  
A.A. Vedyagin ◽  
I.V. Mishakov ◽  
A.S. Noskov
Keyword(s):  
Mathematical Model ◽  
Membrane Reactor ◽  
Ceramic Membrane ◽  
Porous Ceramic ◽  
Porous Membrane ◽  
Membrane Reactors ◽  
Catalytic Membrane ◽  
Catalytic Membrane Reactor ◽  
Membrane Pore ◽  
Ethylbenzene Dehydrogenation

AbstractThe modeling of ethylbenzene dehydrogenation in a catalytic membrane reactor has been carried out for porous membrane by means of two-dimensional, non-isothermal stationary mathematical model. A mathematical model of the catalytic membrane reactor was applied, in order to study the effects of transport properties of the porous membrane on process performance. The performed modeling of the heat and mass transfer processes within the porous membrane, allowed us to estimate the efficiency of its use in membrane reactors, in comparison with a dense membrane (with additional oxidation of the hydrogen in shell side). The use of a porous ceramic membrane was found to cause an increase of the ethylbenzene conversion at 600°C, up to 93 %, while the conversion in the case of conventional reactor was 67%. In this work, we defined the key parameter values of porous membrane (pore diameter and thickness) for ethylbenzene dehydrogenation in catalytic membrane reactor, at which the highest conversion of ethylbenzene and styrene selectivity can be reached.

scholarly journals The protein structures that shape caspase activity, specificity, activation and inhibition

2004 ◽  
Vol 384 (2) ◽  
pp. 201-232 ◽  
Author(s):  
Pablo FUENTES-PRIOR ◽  
Guy S. SALVESEN
Keyword(s):  
Catalytic Mechanism ◽  
Protein Structures ◽  
Limited Proteolysis ◽  
Point Of View ◽  
Coagulation Cascade ◽  
Structural Basis ◽  
Apoptotic Pathway ◽  
Naturally Occurring ◽  
The Many ◽  
Apoptosis Regulation

The death morphology commonly known as apoptosis results from a post-translational pathway driven largely by specific limited proteolysis. In the last decade the structural basis for apoptosis regulation has moved from nothing to ‘quite good’, and we now know the fundamental structures of examples from the initiator phase, the pre-mitochondrial regulator phase, the executioner phase, inhibitors and their antagonists, and even the structures of some substrates. The field is as well advanced as the best known of proteolytic pathways, the coagulation cascade. Fundamentally new mechanisms in protease regulation have been disclosed. Structural evidence suggests that caspases have an unusual catalytic mechanism, and that they are activated by apparently unrelated events, depending on which position in the apoptotic pathway they occupy. Some naturally occurring caspase inhibitors have adopted classic inhibition strategies, but other have revealed completely novel mechanisms. All of the structural and mechanistic information can, and is, being applied to drive therapeutic strategies to combat overactivation of apoptosis in degenerative disease, and underactivation in neoplasia. We present a comprehensive review of the caspases, their regulators and inhibitors from a structural and mechanistic point of view, and with an aim to consolidate the many threads that define the rapid growth of this field.

scholarly journals Proteases Immobilization for In Situ Time-Limited Proteolysis on MALDI Chips

Catalysts ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 833 ◽  
Author(s):  
Rosulek ◽  
Darebna ◽  
Pompach ◽  
Slavata ◽  
Novak
Keyword(s):  
Mass Spectrometry ◽  
Indium Tin Oxide ◽  
Proteolytic Enzymes ◽  
Protein Structures ◽  
Limited Proteolysis ◽  
Covalent Bond ◽  
Maldi Mass Spectrometry ◽  
Clinical Diagnostics ◽  
Oxide Glass

A large number of different enzyme immobilization techniques are used in the field of life sciences, clinical diagnostics, or biotechnology. Most of them are based on a chemically mediated formation of covalent bond between an enzyme and support material. The covalent bond formation is usually associated with changes of the enzymes’ three-dimensional structure that can lead to reduction of enzyme activity. The present work demonstrates a potential of an ambient ion-landing technique to effectively immobilize enzymes on conductive supports for direct matrix-assisted laser desorption/ionization (MALDI) mass spectrometry analyses of reaction products. Ambient ion landing is an electrospray-based technique allowing strong and stable noncovalent and nondestructive enzyme deposition onto conductive supports. Three serine proteolytic enzymes including trypsin, α-chymotrypsin, and subtilisin A were immobilized onto conductive indium tin oxide glass slides compatible with MALDI mass spectrometry. The functionalized MALDI chips were used for in situ time-limited proteolysis of proteins and protein–ligand complexes to monitor their structural changes under different conditions. The data from limited proteolysis using MALDI chips fits to known or predicted protein structures. The results show that functionalized MALDI chips are sensitive, robust, and fast and might be automated for general use in the field of structural biology.

scholarly journals Experimental Investigation of the Oxidative Coupling of Methane in a Porous Membrane Reactor: Relevance of Back-Permeation

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 152 ◽  
Author(s):  
Aitor Cruellas ◽  
Wout Ververs ◽  
Martin van Sint Annaland ◽  
Fausto Gallucci
Keyword(s):  
Oxidative Coupling ◽  
Membrane Reactor ◽  
Effective Diffusion ◽  
Packed Bed ◽  
Porous Membrane ◽  
Oxidative Coupling Of Methane ◽  
Membrane Reactors ◽  
Packed Bed Reactor ◽  
Membrane Properties ◽  
Beneficial Effects

Novel reactor configurations for the oxidative coupling of methane (OCM), and in particular membrane reactors, contribute toward reaching the yield required to make the process competitive at the industrial scale. Therefore, in this work, the conventional OCM packed bed reactor using a Mn-Na2WO4/SiO2 catalyst was experimentally compared with a membrane reactor, in which a symmetric MgO porous membrane was integrated. The beneficial effects of distributive feeding of oxygen along the membrane, which is the main advantage of the porous membrane reactor, were demonstrated, although no significant differences in terms of performance were observed because of the adverse effects of back-permeation prevailing in the experiments. A sensitivity analysis carried out on the effective diffusion coefficient also indicated the necessity of properly tuning the membrane properties to achieve the expected promising results, highlighting how this tuning could be addressed.

Gelation of .beta.-lactoglobulin treated with limited proteolysis by immobilized trypsin

1994 ◽  
Vol 42 (2) ◽  
pp. 234-239 ◽  
Author(s):  
Sharon X. Chen ◽  
Harold E. Swaisgood ◽  
E. Allen Foegeding
Keyword(s):  
Limited Proteolysis ◽  
Immobilized Trypsin ◽  
Beta Lactoglobulin

Modelling of the Membrane Permeability Effect on the H2 Production Using CFD Method

2014 ◽  
Vol 12 (1) ◽  
pp. 333-344 ◽  
Author(s):  
Yacine Benguerba ◽  
Christine Dumas ◽  
Barbara Ernst
Keyword(s):  
Three Dimensional ◽  
Porous Membrane ◽  
H2 Production ◽  
Operating Conditions ◽  
Membrane Reactors ◽  
Production Of Hydrogen ◽  
Different Temperatures ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method ◽  
Supported Ni

Abstract Autothermal reforming of CH4 in a membrane catalytic microreactor for the production of hydrogen at different temperatures over supported Ni catalysts has been studied. A three-dimensional mathematical model was developed using a computational fluid dynamics (CFD) technique. The effect of using different membranes on the performance of the micro-reactor was analysed. The amounts of hydrogen produced and separated in each case, under the same operating conditions, were compared. It was proven that using the porous membrane (Ni–Al2O3) could be an economic solution for the production and separation of hydrogen in membrane reactors.

CHARACTERIZATION OF LIMITED PROTEOLYTIC DIGESTS OF TISSUE PLASMINOGEN ACTIVATOR

1987 ◽  
Author(s):  
G Teshima ◽  
R Harris ◽  
R Keck ◽  
A Meunier ◽  
J Burnier ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Limited Proteolysis ◽  
Single Chain ◽  
Amidolytic Activity ◽  
Amino Terminal ◽  
Tissue Plasminogen ◽  
Limited Digestion ◽  
Chain Form

Tissue plasminogen activator (tPA) is a single chain glycoprotein of 527 amino acids consisting of structural domains homologous to other plasma proteins ("finger","epidermal growth factor", "kringles" and "protease"). Unlike zymogens of other serine proteases, tPA in the single chain form (1-527), has amidolytic and fibrinolytic activity. However, the amidolytic activity is enhanced when tPA is cleaved by plasmin at the Arg275-Ile276 bond to yield the disulfide bonded two chain form. We used trypsin to study the structure and function of tPA by limited digestion. Aliquots of tPA (1 mg/ml) were digested at pH 7 with varying amounts of trypsin (1:10,000, 1:1000, 1:100 and 1:10; enzyme to substrate ratio). The dilute solutions of trypsin (1:10,000) were effective at completely converting one chain tPA to the two chain form, but little additional proteolysis was observed on SDS-PAGE. The proteolytic fragments of tPA were isolated by reduction and carboxymethylation (RCM), SDS gel electrophoresis and reversed phase HPLC. The RCM polypeptides were identified by amino acid composition and sequence. Specific antisera were prepared against peptide antigens of tPA including (1-27), (1-275), (276-527) and (502525). Immunoblotting experiments with the tryptic digests of tPA indicated that the region (1-275) is more susceptible to proteolytic attack than the protease (275-527). Specific cleavage sites were identified at positions 7, 10, 27 and 40. Partially digested tPA preparations were tested for enzymatic activity as determined by hydrolysis of the peptide substrate S-2288 or by clot lysis. Limited proteolysis at the amino terminus was correlated with significant loss of fibrinolytic . activity but minimal effect on the amidolytic activity. Increased tryptic digestion resulted in complete loss of amidolytic activity and significant reduction in antigenic activity as determined by polyclonal anti-tPA ELISA. These results areconsistent with the amino terminal "finger" domain being in part responsible for the fibrin-binding specificity of tPA. Limited tryptic digest of tPA, cleaves first at Arg-275, then subsequently cleaves the "finger" with associated loss of fibrinolytic activity.

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