Identification of aspirinase with one of the carboxylesterases requiring a thiol group.
Ontology highlight
ABSTRACT:
SUBMITTER: White KN
PROVIDER: S-EPMC1163196 | biostudies-other | 1981 Sep
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Monomeric intracellular mouse immunoglobulin M (hereafter designated IgMs) was purified in milligram quantities from the plasma cells of mouse plasmacytoma MOPC 104E after lysis either in the presence or in the absence of iodoacetate. Peptide ;mapping' analysis of the IgMs after partial reduction and carboxy[(14)C]methylation to label the interchain disulphide bridges showed that the heavy-light bridge and the interheavy bridge present in the Cmu2 region were already formed at lysis. The cysteine residues in the C-terminal region of the heavy chains, which in pentameric IgM form an intersubunit bridge, had free thiol groups at lysis that were reversibly oxidized during isolation in the absence of iodoacetate, probably forming an intrasubunit inter-heavy-chain disulphide bridge. Isoelectric-focusing studies complemented the above findings, showing that all the intracellular IgMs carried free thiol groups that could be carboxymethylated at lysis, and that in non-alkylated preparations these had reversibly oxidized. On the basis of sodium dodecyl sulphate/polyacrylamide-slab-gel electrophoresis intracellular mu-chains had a consistently lower apparent molecular weight than did secreted mu-chains, and the estimated difference could be accounted for by the known difference in carbohydrate content. We present evidence that in a position homologous to that of a complex oligosaccharide in the Cmu2 region of secreted human mu-chains there is a simple oligosaccharide in intracellular mouse mu-chains that becomes complex on secretion. On the basis of the above findings, we present a model for the mouse intracellular IgM subunit and suggest a mechanism for its assembly into secreted IgM pentamers.
| S-EPMC1186159 | biostudies-other
Project description:Photoremovable protecting groups are important for a wide range of applications in peptide chemistry. Using Fmoc-Cys(Bhc-MOM)-OH, peptides containing a Bhc-protected cysteine residue can be easily prepared. However, such protected thiols can undergo isomerization to a dead-end product (a 4-methylcoumarin-3-yl thioether) upon photolysis. To circumvent that photoisomerization problem, we explored the use of nitrodibenzofuran (NDBF) for thiol protection by preparing cysteine-containing peptides where the thiol is masked with an NDBF group. This was accomplished by synthesizing Fmoc-Cys(NDBF)-OH and incorporating that residue into peptides by standard solid-phase peptide synthesis procedures. Irradiation with 365 nm light or two-photon excitation with 800 nm light resulted in efficient deprotection. To probe biological utility, thiol group uncaging was carried out using a peptide derived from the protein K-Ras4B to yield a sequence that is a known substrate for protein farnesyltransferase; irradiation of the NDBF-caged peptide in the presence of the enzyme resulted in the formation of the farnesylated product. Additionally, incubation of human ovarian carcinoma (SKOV3) cells with an NDBF-caged version of a farnesylated peptide followed by UV irradiation resulted in migration of the peptide from the cytosol/Golgi to the plasma membrane due to enzymatic palmitoylation. Overall, the high cleavage efficiency devoid of side reactions and significant two-photon cross-section of NDBF render it superior to Bhc for thiol group caging. This protecting group should be useful for a plethora of applications ranging from the development of light-activatable cysteine-containing peptides to the development of light-sensitive biomaterials.
| S-EPMC5026405 | biostudies-literature
Project description:We describe the first one-pot orthogonal strategy to prepare well-defined cyclopeptide-based heteroglycoclusters (hGCs) from glycosyl thiols. Both thiol-chloroactetyl coupling (TCC) and thiol-ene coupling (TEC) have been used to decorate cyclopeptides regioselectively with diverse combination of sugars. We demonstrate that the reaction sequence starting with TCC can be performed one-pot whereas the reverse sequence requires a purification step after the TEC reaction. The versatility of this orthogonal strategy has been demonstrated through the synthesis of diverse hGCs displaying alternating binary combinations of α-D-Man or β-D-GlcNAc, thus providing rapid access to attractive heteroglycosylated platforms for diverse biological applications.
| S-EPMC4142873 | biostudies-literature
Project description:BackgroundBoth groups A and AB plasma have been approved for emergency-release transfusion in acutely bleeding trauma patients before blood grouping being performed. The safety profile associated with this practice has not been well characterized, particularly in patients requiring massive transfusion.MethodsThis secondary analysis of the Pragmatic, Randomized, Optimal Platelet and Plasma Ratios trial examined whether exposure to group A emergency-release plasma (ERP) was noninferior to group AB ERP. We also examined patients whose blood groups were compatible with group A ERP versus patients whose blood groups were incompatible with group A ERP. Outcomes included 30-day mortality and complication rates including systemic inflammatory response syndrome, infection, renal injury, pulmonary dysfunction, and thromboembolism.ResultsOf the 680 patients predicted to receive a massive transfusion, 584 (85.9%) received at least 1 U of ERP. Of the 584 patients analyzed, 462 (79.1%) received group AB and 122 (20.9%) received group A ERP. Using a hazard ratio (HR) of 1.35 as the noninferiority margin, transfusion with group A versus group AB ERP was not associated with increased thromboembolic rates (HR, 0.52; 95% confidence interval [CI], 0.31-0.90). Mortality (HR, 1.15; 95% CI, 0.91-1.45) and nonfatal complication rates (HR, 1.24; 95% CI, 0.87-1.77) were inconclusive. In the subgroup analysis, transfusion with incompatible ERP (group B or AB patients receiving group A ERP) was not associated with increased nonfatal complications (HR, 1.02; 95% CI, 0.80-1.30). There were no reported hemolytic transfusion reactions.ConclusionThe use of ERP is common in patients requiring massive transfusion and facilitates the rapid balanced resuscitation of patients who have sustained blood loss. Group A ERP is an acceptable option for patients requiring massive transfusion, especially if group AB ERP is not readily available.Level of evidenceTherapeutic/Care Management, level IV; Prognostic, level III.
| S-EPMC7830815 | biostudies-literature
Project description:The novel tris(4-azidophenyl)methanol, a multifunctionalisable aryl azide, is reported. The aryl azide can be used as a protecting group for thiols in peptoid synthesis and can be cleaved under mild reaction conditions via a Staudinger reduction. Moreover, the easily accessible aryl azide can be functionalised via copper-catalysed cycloaddition reactions, providing additional opportunities for materials chemistry applications.
| S-EPMC9844210 | biostudies-literature
Project description:Gold nanoclusters (AuNCs) and liquid crystals (LCs) have shown great potential in nanobiotechnology applications due to their unique optical and structural properties. Herein, the hardcore of the 4-cyano biphenyl group for commonly used LCs of 4-cyano-4'-pentylbiphenyl (5CB) was utilized to synthesize 4'-(2-mercaptoethyl)-(1,1'-biphenyl)-4-carbonitrile (TAT-12) based on Suzuki coupling and Appel reaction. The structural and optical properties of thiol-modified TAT-12 LCs were demonstrated by nuclear magnetic resonance (NMR) spectroscopy, ultraviolet-visible (UV-vis) spectroscopy and differential scanning calorimetry (DSC). By one-pot synthesis, thiol-modified TAT-12 LCs were used as the ligands to prepare fluorescent gold nanoclusters (AuNCs@TAT-12) according to the Au-S bond between AuNCs and TAT-12. The spectra of UV-vis absorption and X-ray photoelectron spectroscopy (XPS) of AuNCs@TAT-12 indicated that the core of gold of AuNCs@TAT-12 exhibited high gold oxidation states. The fluorescence of AuNCs@TAT-12 was observed with a maximum intensity at ~352 nm coming from TAT-12 on AuNCs@TAT-12 and the fluorescence quantum yield of AuNCs@TAT-12 was calculated to be 10.1%. Furthermore, the fluorescence with a maximum intensity at ~448 nm was attributed to a ligand-metal charge transfer between the ligands of TAT-12 LCs and the core of AuNCs. The image of transmission electron microscopy (TEM) further demonstrated an approximately spherical shape of AuNCs@TAT-12 with an average size of 2.3 nm. A combination of UV-vis absorption spectra, XPS spectra, fluorescence spectra and TEM image, fluorescent AuNCs@TAT-12 were successfully synthesized via one-pot synthesis. Our work provides a practical approach to the synthesis of LCs conjugated AuNCs for future applications in nanobiotechnology.
| S-EPMC7558681 | biostudies-literature
Project description:Maleimide chemistry is widely used in the site-selective modification of proteins. However, hydrolysis of the resultant thiosuccinimides is required to provide robust stability to the bioconjugates. Herein, we present an alternative approach that affords simultaneous stabilisation and dual functionalisation in a one pot fashion. By consecutive conjugation of a thiol and an amine to dibromomaleimides, we show that aminothiomaleimides can be generated extremely efficiently. Furthermore, the amine serves to deactivate the electrophilicity of the maleimide, precluding further reactivity and hence generating stable conjugates. We have applied this conjugation strategy to peptides and proteins to generate stabilised trifunctional conjugates. We propose that this stabilisation-dual modification strategy could have widespread use in the generation of diverse conjugates.
| S-EPMC8162801 | biostudies-literature
Project description:N-(2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl)-6-fluoronicotinamide ([(18)F]FNEM), a novel prosthetic agent that is thiol-specific, was synthesized using a one-pot two-step strategy: (1) (18)F incorporation by a nucleophilic displacement of trimethylammonium substrate under mild conditions; (2) amidation of the resulting 6-[(18)F]fluoronicotinic acid 2,3,5,6-tetrafluorophenyl ester with N-(2-aminoethyl)maleimide trifluoroacetate salt. The radiosynthesis of the maleimide tracer was completed in 75 min from [(18)F]fluoride with 26 ± 5% decay uncorrected radiochemical yield, and specific activity of 19-88 GBq/μmol (decay uncorrected). The in vitro cell uptake, in vivo biodistribution, and positron emission tomography (PET) imaging properties of its conjugation product with [Cys(40)]-exendin-4 were described. [(18)F]FNEM-Cys(40)-exendin-4 showed specific targeting of glucagon-like peptide 1 receptor (GLP-1R) positive insulinomas and comparable imaging results to our recently reported [(18)F]FPenM-Cys(40)-exendin-4.
| S-EPMC4224565 | biostudies-other
Project description:The crystal structures of 6-meth-oxy-1,3-benzoxa-thiol-2-one, C9H8O3S, (I), and 2-oxo-1,3-benzoxa-thiol-6-yl acetate, C9H6O4S, (II), are described. Compound (I) is almost planar (r.m.s. deviation for the non-H atoms = 0.011 Å), whereas (II) shows a substantial twist between the fused-ring system and the acetate substituent [dihedral angle = 74.42 (3)°]. For both structures, the bond distances in the heterocyclic ring suggest that little if any conjugation occurs. In the crystal of (I), C-H⋯O hydrogen bonds link the mol-ecules into [1-11] chains incorporating alternating R22(8) and R22(12) inversion dimers. The extended structure of (II) features C(7) [201] chains linked by C-H⋯O hydrogen bonds, with further C-H⋯O bonds and weak π-π stacking inter-actions connecting the chains into a three-dimensional network. Hirshfeld fingerprint analyses for (I) and (II) are presented and discussed.
| S-EPMC5778491 | biostudies-literature
Project description:BACKGROUND:Most prognostic studies in acute stroke patients requiring invasive mechanical ventilation are outdated and have limitations such as single-center retrospective designs. We aimed to study the association of ICU admission factors, including the reason for intubation, with 1-year survival of acute stroke patients requiring mechanical ventilation. METHODS:We conducted a secondary data use analysis of a prospective multicenter database (14 ICUs) between 1997 and 2016 on consecutive ICU stroke patients requiring mechanical ventilation at admission. We excluded patients with stroke of traumatic origin, subdural hematoma or cerebral venous thrombosis. The primary outcome was survival 1 year after ICU admission. Factors associated with the primary outcome were identified using a multivariable Cox model stratified on inclusion center. RESULTS:We identified 419 patients (age 68 [58-76] years, males 60%) with a Glasgow coma score (GCS) of 4 [3-8] at admission. Stroke subtypes were acute ischemic stroke (AIS, 46%), intracranial hemorrhage (ICH, 42%) and subarachnoid hemorrhage (SAH, 12%). At 1 year, 96 (23%) patients were alive. Factors independently associated with decreased 1-year survival were ICH and SAH stroke subtypes, a lower GCS score at admission, a higher non-neurological SOFA score. Conversely, patients receiving acute-phase therapy had improved 1-year survival. Intubation for acute respiratory failure or coma was associated with comparable survival hazard ratios, whereas intubation for seizure was not associated with a worse prognosis than for elective procedure. Survival did not improve over the study period, but patients included in the most recent period had more comorbidities and presented higher severity scores at admission. CONCLUSIONS:In acute stroke patients requiring mechanical ventilation, the reason for intubation and the opportunity to receive acute-phase stroke therapy were independently associated with 1-year survival. These variables could assist in the decision process regarding the initiation of mechanical ventilation in acute stroke patients.
| S-EPMC7205929 | biostudies-literature