Search results for "Substrate Specificity"
showing 10 items of 217 documents
γ2-Adaptin, a Ubiquitin-interacting Adaptor, Is a Substrate to Coupled Ubiquitination by the Ubiquitin Ligase Nedd4 and Functions in the Endosomal Pa…
2008
gamma2-Adaptin is a putative member of the clathrin adaptor protein family with unknown physiological function. We previously reported that gamma2-adaptin acts as a ubiquitin receptor by virtue of its ubiquitin-interacting motif. Here we demonstrate that this motif mediates a specific physical interaction with the ubiquitin ligase Nedd4 and promotes ubiquitination of gamma2-adaptin. By mapping regions of Nedd4 involved in binding to gamma2-adaptin, we identified its C2 domain to be essential, whereas the WW and HECT domains are dispensable. Consistent with this, we uncovered that the C2 domain of Nedd4 is ubiquitinated itself and as such is recruited by the ubiquitin-interacting motif of ga…
Embedding “substrate” in environmental assessment of green roofs life cycle: evidences from an application to the whole chain in a Mediterranean site
2012
Abstract A classical LCA methodology is here applied to green roofs including in this analysis also the whole life cycle of the substrate, that represented a lack of previous LCA studies on green roofs. This inclusion will allow a complete and proper application of the LCA methodology to achieve an environmental accounting of the “green roof” performance. We have here chosen to approach the problem by analysing a specific substrate, that is used within an actual extensive green roof. Afterwards, we have applied the LCA methodology to the whole actual extensive green roof whose substrate under analysis is part of. In this manner, we achieved an environmental accounting of the “green roof” pe…
Specificity of mouse liver cytosolic epoxide hydrolase for K-region epoxides derived from polycyclic aromatic hydrocarbons
1980
Mouse liver cytosol epoxide hydrolase, known to be very active for certain alkene oxides, had a specific activity which was 2.1-, 11- and 160-fold lower than that of the microsomal epoxide hydrolase for the arene oxides 7-methylbenz[a]anthracene 5,6-oxide, benz[a]anthracene 5,6-oxide and phenanthrene 9,10-oxide, respectively. For benzo[a]pyrene 4,5-oxide no activity (less than 10 pmol product/mg protein/min) of cytoplasmic epoxide hydrolase was detectable. The specific activity of cytoplasmic epoxide hydrolase was much lower for all K-region epoxides investigated, compared to trans-stilbene oxide used as a positive control and for which a new assay is described. It is concluded from these r…
Enzymes involved in the dynamic equilibrium of core histone acetylation ofPhysarum polycephalum
1992
DEAE-Scpharose chromatography of extracts from plasmodia of the myxomyccte PI~.~suru~~t ,~/.~crpl~~ho~~ revealed the presence of multiple histone acetyltransferases and histonc deacctylascs. A cyloplasmic histonc acctyltransferase B, specific for histonc H4, and two nuclear acetyltransferases Al and A2 were identilied; Al acetylates all core hislones with a preference for l-13 and H2A. whereas A2 is specific for H3 and also slightly for H2B. Two hislone deacetylases. HDI and HD2, could be discriminated. They differ with respect to subslralc speciliciiy and pH dependence. For the first time the substrate specificity of histonc deacetylascs was determined using HPLC-purilicd individual core h…
Phosphotransferase properties of human erythrocyte phosphoglycolate phosphatase.
1982
Abstract 1. 1. Human erythrocyte phosphoglycolate phosphatase (PGP) (EC 3.1.3.18) shows transferase properties. Using p -nitrophenylphosphate ( p -NPP) as substrate, methanol, at a concentration of 4.9 M. was the most efficient phosphate acceptor tested (60% phosphate transfer). 2. 2. The branched alcohols i -propanol and i -butanol accept the phosphate better than the unbranched compounds. The acceptor potency is methanol > ethanol > i -propanol > n -propanol > i -butanol > n -butanol. 3. 3. The relative transferase activity could be demonstrated to be independent of substrate concentration, pH. and the inhibitory effect of NaF at 2 and 4 mM. 4. 4. POP shows no transferase activity towards…
Digestive vacuoles of Plasmodium falciparum are selectively phagocytosed by and impair killing function of polymorphonuclear leukocytes.
2011
AbstractSequestration of parasitized erythrocytes and dysregulation of the coagulation and complement system are hallmarks of severe Plasmodium falciparum malaria. A link between these events emerged through the discovery that the parasite digestive vacuole (DV), which is released together with infective merozoites into the bloodstream, dually activates the intrinsic clotting and alternative complement pathway. Complement attack occurs exclusively on the membrane of the DVs, and the question followed whether DVs might be marked for uptake by polymorphonuclear granulocytes (PMNs). We report that DVs are indeed rapidly phagocytosed by PMNs after schizont rupture in active human serum. Uptake …
Neutral deoxyribonucleases of HeLa S3 cells: electrophoretic separation, characterization, substrate specificity and mode of action.
1980
Extracts of HeLa S3 cells were electrophoresed on polyacrylamide gels; gel slices were eluted and the eluates were assayed for DNase activities against native and denatured DNA substrates in the presence of MgCl2 or Na2EDTA. Aliquots of each eluate were also assayed for their ability to nick the circular supercoiled PM2 phage DNA to distinguish endonucleases from exonucleases. Peaks of endonuclease activities were characterized as forming 3′-phospho-oligonucleotides or 5′-phospho-oligonucleotides by the use of oligonucleotides produced by these enzymes as substrates for the 5′-phosphate-specific snake venom exonuclease. The total activity of DNases in gel eluates was much higher than that i…
Delta 5-desaturation of dihomogammalinolenic acid (20:3(n-6)) into arachidonic acid (20:4(n-6)) by rat liver microsomes and incorporation of fatty ac…
1991
Abstract Liver microsomes of rats fed an essential fatty acid (EFA)-deficient diet or a commercial balanced diet were used to study the effect of incubation time on the Δ 5 -desaturation of [ 14 C] dihomogammalinolenic acid (20:3( n −6)) into arachidonic acid (20:4( n −6)) and incorporation of the two acids into microsomal phospholipids. The EFA-deficient diet highly increased the desaturation rate of 20:3( n −6). Incorporation of the formed 20:4( n −6) into microsomal phospholipids was also increased but at saturating concentration of substrate only. At early times of incubation, the precursor 20:3( n −6) was rapidly incorporated into phospholipids. Formation and incorporation of 20:4( n −…
Identification of P-glycoprotein substrates and inhibitors among psychoactive compounds--implications for pharmacokinetics of selected substrates.
2004
Abstract The pharmacokinetics of antipsychotic drugs has become an integral part in understanding their pharmacodynamic activity and clinical effects. In addition to metabolism aspects, carrier-mediated transport, particularly secretion by ABC transporters, has been discussed as potentially relevant for this group of therapeutics. In this study, the psychoactive compounds perphenazine, flupentixol, domperidone, desmethyl clozapine, haloperidol, fluphenazine, fluvoxamine, olanzapine, levome-promazine, perazine, desmethyl perazine, clozapine, quetiapine and amisulpride were characterized in terms of P-glycoprotein (P-gp) affinity and transport. Experimental methods involved a radioligand disp…
Binding and/or hydrolysis of purine‐based nucleotides is not required for IM30 ring formation
2021
IM30, the inner membrane-associated protein of 30 kDa, is conserved in cyanobacteria and chloroplasts. Although its exact physiological function is still mysterious, IM30 is clearly essential for thylakoid membrane biogenesis and/or dynamics. Recently, a cryptic IM30 GTPase activity has been reported, albeit thus far no physiological function has been attributed to this. Yet, it is still possible that GTP binding/hydrolysis affects formation of the prototypical large homo-oligomeric IM30 ring and rod structures. Here, we show that the Synechocystis sp. PCC 6803 IM30 protein in fact is an NTPase that hydrolyzes GTP and ATP, but not CTP or UTP, with about identical rates. While IM30 forms lar…