Tài liệu Báo cáo khoa học: High activity of human butyrylcholinesterase at low pH in the presence of excess butyrylthiocholine pptx

... butyrylcho-linesterase does not operate for catalysis at low pH. The mechanism explaining the catalytic behaviour of butyryl-cholinesterase at low pH in the presence of excess substrateremains to ... between bkcatand kcat at high pH is large relative to the difference at low pH, and the difference between bkcat at high pH and bkcat at low pH is relatively large (Fig. 5). In all of these enzymes, ... pKavalues of 6.0–6.6, suggestingthat the catalytic histidine is protonated at pH 5. The existence of activity when the catalytic histidine is protonatedindicates that the catalytic-triad mechanism of...

Tài liệu Báo cáo khoa học: High-afﬁnity ligand binding by wild-type/mutant heteromeric complexes of the mannose pptx

... that the I1572T mutation residing in the heart of the IGF-II binding domain in repeat 11 disruptsIGF-II binding to the receptor [22,31–33]. The ligandblotting data shown in Fig. 1C conﬁrm that ... (B). The lines in each graph indicate the amount of binding predicted if the wild-type and mutant receptors are bindingligand independently. The triangles indicate a progressive shift in the ratio ... that the percentage of binding based oncontributions of the mutant (no binding activity) andwild-type (100% binding activity) mini-receptors in the mixture would follow the line displayed in...

Tài liệu Báo cáo khoa học: Accessibility changes within diphtheria toxin T domain when in the functional molten globule state, as determined using hydrogen⁄deuterium exchange measurements pdf

... state, which initi-ates the translocation of the catalytic domain. Here, the data allowed identiﬁcation of the core of the pro-tein in the N state and the evolution of the overallstructure of ... exchange The T domain was dissolved in 4 mm citrate-phosphate buf-fer, pH 7.0, at a concentration of 70 lm. One part of the solution was kept at pH 7.0 and in the other the pH waslowered to 4.0 by the ... identify the core of the pro-tein in the N- and MG states, the regions of moderateand high accessibility, and regions involved in the olig-omerization of both states of the T domain in solution.ResultsMonitoring...

Tài liệu Báo cáo khoa học: Autolytic activity of human calpain 7 is enhanced by ESCRT-III-related protein IST1 through MIT–MIM interaction pptx

... anti-GFP-reacting 30 kDa band was not detected in the immunoprecipitates of antibody against calpain 7,indicating a lack of MIT domains in 30 K. Thus,mGFP–calpain 7 contains at least two cleavage ... lies at the N-terminal boundary of the proteasedomain, generating 45 K, and the other lies betweenmGFP and MITa, generating 30 K (Fig. 6A). Toroughly estimate the latter cleavage site in mGFP–cal-pain ... suggestedthat mGFP–calpain 7 was cleaved at the point immedi-ately after or in the vicinity of residue 239 of mGFP. In order to determine an autolytic cleavage site in mGFP–calpain 7–Strep, we also attempted...

Tài liệu Báo cáo khoa học: High afﬁnity copper binding by steﬁn B (cystatin B) and its role in the inhibition of amyloid ﬁbrillation docx

... afﬁnitycopper binding protein, and (b) that amyloid ﬁbrilformation of this protein is diminished in presence of Cu2+ions. Another interesting ﬁnding is thatcopper binding gets less strong at pH 5, ... subtraction of data from a series of injections of copper chelate solutioninto a buffer blank correlating to the heat of dilution of the copper complex. After subtraction of the blank data a non-linear ... cor-responding peak from the Superdex 75 column, then, the monomer was incubated (see above) in the presence of Cu2+and without Cu2+, at pH 5 and pH 7. The mobilephase was 0.01 m phosphate buffer,...

Tài liệu Báo cáo khoa học: ATPase activity of magnesium chelatase subunit I is required to maintain subunit D in vivo ppt

... double-ringed BchI-BchD structure the ATPase activity of BchI isblocked. A conformational transition upon binding toBchH may bring the integrin I domain of BchD into contactwith the integrin-binding ... integrin-binding motif of BchH, simultaneouslytriggering porphyrin metallation. This would also lead to arelease of the blockade of the ATP-binding site of BchI by the integrin I domain, triggering ATP hydrolysis ... and thatbinding between the two subunits is not suﬃcient tomaintain the 70 kDa subunit in the cell. The ATPasedeﬁcient 40 kDa proteins fail to participate in chelation in a step after the association...

Tài liệu Báo cáo khoa học: Structure-activity relationships of a-conotoxins targeting neuronal nicotinic acetylcholine receptors ppt

... understanding the complexity involved in binding to the nAChR. A summary of this structuralinformation and the insights into structure -activity relation-ships of a-conotoxins is presented in this ... attributed to the longerside chain of the leucine at position 10. In general, for the 4/7 a-conotoxins there appears to be a correlation between the length of the aliphatic side chain in position ... that of the native conotoxin and maintained the activity for the a3b2 subtype activity associated with the native peptide. However the 5LaaMII peptide did not adopt the helical structure seen in...

Tài liệu Báo cáo khoa học: KIPase activity is a novel caspase-like activity associated with cell proliferation doc

... KIPase activity in the indicated cell lines was assessedusing the same assay. The data are expressed relative to the activity measured in the absence of z-VAD-fmk. In test assays z-VAD-fmk inhibited human ... the cells were incubated for4 h at 37 °C (in triplicate). The cells were then harvestedonto ﬁlters and the incorporation of labelled thymidine intoinsoluble material was determined [1]. To prepare ... proliferating and arrested populations of cells.[3H]Thymidine incorporation assays conﬁrmed the status of the populations; arrested cells incorporated four-fold less[3H]thymidine than the proliferating...

Tài liệu Báo cáo khoa học: Endotoxic activity and chemical structure of lipopolysaccharides from Chlamydia trachomatis serotypes E and L2 and Chlamydophila psittaci 6BC pdf

... [20]. At low LPS concentrations, blocking of CD14 completely abro-gated stimulation of human MNC. We investigated the remaining stimulatory activity of all LPS preparations afterpreincubation ... fragmentions of the de-O-acylated lipid A moiety around m/z 1119.75,and ions of minor intensity originating from the consecutiveloss of three Kdo residues. Further ions observed in the spectrum originated ... containing 2% N-lauroylsarco-sine sodium salt in water (w/v), heated at 68 °Cfor10minand cooled on ice. After centrifugation (3000 g, 30 min), the water phase was removed and the phenol phase...

Tài liệu Báo cáo khoa học: NirF is a periplasmic protein that binds d1 heme as part of its essential role in d1 heme biogenesis pdf

... in loss of in vivoNirF activity. We demonstrate here that the product of the nirF gene is aperiplasmic protein and, hence, must be involved in a late stage of the cofac-tor biosynthesis. In ... Alfred Phu¨ler at the University of Biele-feld are thanked for their kind gift of plasmid pMS255.Dr Katalin di Gleria at The Weatherall Institute of Molecular Medicine, University of Oxford ... nucleotide-bind-ing motif in the N-terminal of the protein sequenceand also because there is a need for oxidation in the d1heme biosynthetic pathway, for example, oxidation of C17 propionate to...

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