Alkaline phophatase from the hepatopancreas of shrimp (Pandalus borealis): A dimeric enzyme with catalytically active subunits

1991 ◽  
Vol 99 (4) ◽  
pp. 755-761 ◽  
Author(s):  
Ragnar L. Olsen ◽  
Kersti Øverbø ◽  
Bjørnar Myrnes
Keyword(s):  
Pandalus Borealis ◽  
Catalytically Active ◽  
Active Subunits ◽  
Alkaline Phophatase

scholarly journals Self-assembly Is Prerequisite for Catalysis of Fe(II) Oxidation by Catalytically Active Subunits of Ferritin

2015 ◽  
Vol 290 (44) ◽  
pp. 26801-26810 ◽  
Author(s):  
Kourosh Honarmand Ebrahimi ◽  
Peter-Leon Hagedoorn ◽  
Wilfred R. Hagen
Keyword(s):  
Self Assembly ◽  
Catalytically Active ◽  
Active Subunits

scholarly journals Reversible dissociation of the catalytically active subunits of pigeon liver malic enzyme

1988 ◽  
Vol 254 (1) ◽  
pp. 123-130 ◽  
Author(s):  
G G Chang ◽  
T M Huang ◽  
T C Chang
Keyword(s):  
Malic Enzyme ◽  
Quaternary Structure ◽  
Polyacrylamide Gel Electrophoresis ◽  
Reversible Dissociation ◽  
Combined Use ◽  
Catalytically Active ◽  
Enzyme Subunits ◽  
Active Subunits ◽  
Pigeon Liver ◽  
Chemical Cross Linking

The pH-induced reversible dissociation of pigeon liver malic enzyme (EC 1.1.1.40) was studied by combined use of chemical cross-linking and SDS/polyacrylamide-gel electrophoresis. The tetrameric enzyme showed a pH-dependent dissociation in an acidic environment. At pH values above 8.0 most molecules existed as tetramers. The enzyme was gradually dissociated at lower pH. When the pH was below 5.0 most of the enzyme was present as the monomeric forms. Reassociation of the subunits was accomplished by adjusting the pH to neutrality. The dissociation and reassociation were almost instantaneous. No trimer was detected. The pigeon liver malic enzyme was thus shown to have a double-dimer quaternary structure with D2 symmetry. In the presence of substrates, the monomer-dimer-tetramer equilibrium favours the direction of dissociation. Tartronate, an L-malate analogue, was found to be more effective than L-malate in this process. When the monomeric forms were immobilized, the enzyme subunits were found to be fully active in catalysis. A possible arrangement of the four identical subunits of the enzyme molecule is proposed to account for the results obtained in this investigation. The origin of the half-of-the-sites reactivity of pigeon liver malic enzyme is also discussed.

Proteasome Inhibitor Drugs

2020 ◽  
Vol 60 (1) ◽  
pp. 457-476 ◽  
Author(s):  
Lloyd D. Fricker
Keyword(s):  
Proteasome Inhibitor ◽  
Protein Complexes ◽  
Proteasome Inhibitors ◽  
Regulatory Subunits ◽  
Primary Mechanism ◽  
Mantle Cell ◽  
The Us ◽  
Catalytically Active ◽  
Associated Proteins ◽  
Active Subunits

Proteasomes are large, multicatalytic protein complexes that cleave cellular proteins into peptides. There are many distinct forms of proteasomes that differ in catalytically active subunits, regulatory subunits, and associated proteins. Proteasome inhibitors are an important class of drugs for the treatment of multiple myeloma and mantle cell lymphoma, and they are being investigated for other diseases. Bortezomib (Velcade) was the first proteasome inhibitor to be approved by the US Food and Drug Administration. Carfilzomib (Kyprolis) and ixazomib (Ninlaro) have recently been approved, and more drugs are in development. While the primary mechanism of action is inhibition of the proteasome, the downstream events that lead to selective cell death are not entirely clear. Proteasome inhibitors have been found to affect protein turnover but at concentrations that are much higher than those achieved clinically, raising the possibility that some of the effects of proteasome inhibitors are mediated by other mechanisms.

scholarly journals Nedd8 Regulates Inflammasome-Dependent Caspase-1 Activation

2014 ◽  
Vol 35 (3) ◽  
pp. 582-597 ◽  
Author(s):  
Jesus A. Segovia ◽  
Su-Yu Tsai ◽  
Te-Hung Chang ◽  
Niraj K. Shil ◽  
Susan T. Weintraub ◽  
...  
Keyword(s):  
Mass Spectrometric ◽  
Mass Spectrometric Analysis ◽  
Spectrometric Analysis ◽  
Inflammasome Activation ◽  
Activated Macrophages ◽  
Caspase 1 ◽  
293 Cells ◽  
Catalytically Active ◽  
Active Subunits

Caspase-1 is activated by the inflammasome complex to process cytokines like interleukin-1β (IL-1β). Pro-caspase-1 consists of three domains, CARD, p20, and p10. Association of pro-caspase-1 with the inflammasome results in initiation of its autocatalytic activity, culminating in self-cleavage that generates catalytically active subunits (p10 and p20). In the current study, we show that Nedd8 is required for efficient self-cleavage of pro-caspase-1 to generate its catalytically active subunits. Nedd8 silencing or treating cells with the neddylation inhibitor MLN4924 led to diminished caspase-1 processing and reduced IL-1β maturation following inflammasome activation. Coimmunoprecipitation and mass spectrometric analysis of 293 cells overexpressing pro-caspase-1 (and CARD) and Nedd8 suggested possible neddylation of caspase-1 CARD. Following inflammasome activation in primary macrophages, we observed colocalization of endogenous Nedd8 with caspase-1. Similarly, interaction of endogenous Nedd8 with caspase-1 CARD was detected in inflammasome-activated macrophages. Furthermore, enhanced autocatalytic activity of pro-caspase-1 was observed following Nedd8 overexpression in 293 cells, and such activity in inflammasome-activated macrophages was drastically diminished upon treatment of cells with MLN4924. Thus, our studies demonstrate a role of Nedd8 in regulating caspase-1 activation following inflammasome activation, presumably via augmenting autoprocessing/cleavage of pro-caspase-1 into its corresponding catalytically active subunits.

Ru(ii) water oxidation catalysts with 2,3-bis(2-pyridyl)pyrazine and tris(pyrazolyl)methane ligands: assembly of photo-active and catalytically active subunits in a dinuclear structure

2020 ◽  
Vol 49 (10) ◽  
pp. 3341-3352
Author(s):  
Alice de Palo ◽  
Giuseppina La Ganga ◽  
Francesco Nastasi ◽  
Massimo Guelfi ◽  
Marco Bortoluzzi ◽  
...  
Keyword(s):  
Experimental Study ◽  
Water Molecule ◽  
Coordination Sphere ◽  
Water Oxidation ◽  
Oxidation Catalysts ◽  
Catalytically Active ◽  
Active Subunits ◽  
Dinuclear Structure

A combined DFT and experimental study indicates that one water molecule is allowed to enter the first coordination sphere of a one-site catalyst, thus activating water oxidation.

Growth of Catalytically Active Nanostructures in the Nonequilibrium Epitaxy Regime

2015 ◽  
Vol 60 (6) ◽  
pp. 546-552
Author(s):  
V.M. Gorshkov ◽  
◽  
V.V. Kuzmenko
Keyword(s):  
Catalytically Active

Sewage sludge as a precursor of adsorbents/catalysts for environmental applications

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
A. Ros ◽  
C. Canals-Batlle ◽  
M.A. Lillo-Ródenas ◽  
E. Fuente ◽  
M. A. Montes-Morán ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Room Temperature ◽  
Waste Water Treatment ◽  
Textural Properties ◽  
Active Species ◽  
Elemental Sulphur ◽  
Gaseous Emissions ◽  
Removal Experiments ◽  
Catalytically Active

This paper focuses on the valorisation of solid residues obtained from the thermal treatment of sewage sludge. In particular, sewage sludge samples were collected from two waste water treatment plants (WWTPs) with different sludge line basic operations. After drying, sludges were heated up to 700 °C in appropriate ovens under diluted air (gasification) and inert (pyrolysis) atmospheres. The solids obtained, as well as the dried (raw) sludges, were characterised to determine their textural properties and chemical composition, including the speciation of their inorganic fraction. All the materials under study were employed as adsorbents/catalysts in H2S removal experiments at room temperature. It was found that, depending on the particular sludge characteristics, outstanding results can be achieved both in terms of retention capacities and selectivity. Some of the solids outperform commercially available sorbents specially designed for gaseous emissions control. In these adsorbents/catalysts, H2S is selectively oxidised to elemental sulphur most likely due to the presence of inorganic, catalytically active species. The role of the carbon-enriched part on these solids is also remarked.

Sign in / Sign up

Export Citation Format

Share Document