A class of organic compounds that contains a naphthalene moiety linked to a sulfonic acid salt or ester.
A class of organic compounds which contain an anilino (phenylamino) group linked to a salt or ester of naphthalenesulfonic acid. They are frequently used as fluorescent dyes and sulfhydryl reagents.
An enzyme that catalyzes the transfer of the planetary sulfur atom of thiosulfate ion to cyanide ion to form thiocyanate ion. EC 2.8.1.1.
Measurement of the intensity and quality of fluorescence.
Disruption of the non-covalent bonds and/or disulfide bonds responsible for maintaining the three-dimensional shape and activity of the native protein.
Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).

Opposite behavior of two isozymes when refolding in the presence of non-ionic detergents. (1/531)

GroEL has a greater affinity for the mitochondrial isozyme (mAAT) of aspartate aminotransferase than for its cytosolic counterpart (cAAT) (Mattingly JR Jr, Iriarte A, Martinez-Carrion M, 1995, J Biol Chem 270:1138-1148), two proteins that share a high degree of sequence similarity and an almost identical spatial structure. The effect of detergents on the refolding of these large, dimeric isozymes parallels this difference in behavior. The presence of non-ionic detergents such as Triton X-100 or lubrol at concentrations above their critical micelle concentration (CMC) interferes with reactivation of mAAT unfolded in guanidinium chloride but increases the yield of cAAT refolding at low temperatures. The inhibitory effect of detergents on the reactivation of mAAT decreases progressively as the addition of detergents is delayed after starting the refolding reaction. The rate of disappearance of the species with affinity for binding detergents coincides with the slowest of the two rate-limiting steps detected in the refolding pathway of mAAT. Limited proteolysis studies indicate that the overall structure of the detergent-bound mAAT resembles that of the protein in a complex with GroEL. The mAAT folding intermediates trapped in the presence of detergents can resume reactivation either upon dilution of the detergent below its CMC or by adding beta-cyclodextrin. Thus, isolation of otherwise transient productive folding intermediates for further characterization is possible through the use of detergents.  (+info)

Effect of the hemolytic lectin CEL-III from Holothuroidea Cucumaria echinata on the ANS fluorescence responses in sensitive MDCK and resistant CHO cells. (2/531)

The addition of CEL-III to sensitive MDCK cells preincubated with 8-anilino-1-naphthalenesulfonate (ANS) caused an increase in the fluorescence intensity of the probe. The increase in the ANS fluorescence caused by CEL-III was Ca2+-dependent and strongly inhibited by 0.1 M lactose, indicating that Ca2+-dependent binding of CEL-III to specific carbohydrate receptors on the plasma membrane is responsible for this phenomenon. In contrast, no significant effect of CEL-III on the ANS fluorescence was observed in CHO cells, which are highly resistant to CEL-III cytotoxicity. In MDCK cells, energy transfer from tryptophan residues to bound ANS molecules was observed in the presence of CEL-III, but not in CHO cells. Furthermore, the amount of ANS bound to MDCK cells increased as the concentration of CEL-III increased. Therefore, a simple interpretation is that the CEL-III-induced increase in ANS fluorescence is attributable to an increase of the hydrophobic region in the plasma membrane where ANS could bind. Immunoblotting analysis of proteins from cells treated with CEL-III indicated that CEL-III oligomers were irreversibly bound to the cells, and the amount of oligomer bound to MDCK cells was much greater than that bound to CHO cells under any conditions tested. The oligomerization may be accompanied by an enhancement of the hydrophobicity of CEL-III molecules, which in turn provides new ANS-binding sites. The difference in susceptibility of MDCK and CHO cells to CEL-III cytotoxicity may be due to a difference in oligomerization of bound CEL-III.  (+info)

The Mycobacterium tuberculosis small heat shock protein Hsp16.3 exposes hydrophobic surfaces at mild conditions: conformational flexibility and molecular chaperone activity. (3/531)

Hsp16.3, the alpha-crystallin-related small heat shock protein of Mycobacterium tuberculosis that is maximally expressed during the stationary phase and is a major membrane protein, has been reported to form specific trimer-of-trimers structure and to act as an effective molecular chaperone (Chang Z et al., 1996, J. Biol Chem 271:7218-7223). However, little is known about its action mechanism. In this study, Hsp16.3 conformational intermediates with dramatically increased chaperone activities were detected after treatment with very low concentrations of guanidine hydrochloride (0.05 M), urea (0.3 M), or mild heating (30 degrees C). The intermediates showed a significant increase in their capacity to bind the hydrophobic probe 1-anilino-8-naphthalene sulfonate (ANS), indicating an increased exposure of hydrophobic surfaces. Interestingly, the greatest chaperone activities of Hsp16.3 were observed in the presence of 0.3 M guanidine HCl or when heated to 35 degrees C. CD spectroscopy studies revealed no significant changes in protein secondary and tertiary structures at these mild treatments. Our in vitro studies also indicate that long-time-heated Hsp16.3, heated even to temperatures as high as 85 degrees C, has almost the same, if not a slightly greater, chaperone activities as the native protein when cooled to room temperature and its secondary structures also almost recovered. Together, these results suggest that Hsp16.3 modulates its chaperone activity by exposing hydrophobic surfaces and that the protein structure is highly stable and flexible, thus highly adapted for its function.  (+info)

Fluorescence measurements detect changes in scallop myosin regulatory domain. (4/531)

Ca2+-induced conformational changes of scallop myosin regulatory domain (RD) were studied using intrinsic fluorescence. Both the intensity and anisotropy of tryptophan fluorescence decreased significantly upon removal of Ca2+. By making a mutant RD we found that the Ca2+-induced fluorescence change is due mainly to Trp21 of the essential light chain which is located at the unusual Ca2+-binding EF-hand motif of the first domain. This result suggests that Trp21 is in a less hydrophobic and more flexible environment in the Ca2+-free state, supporting a model for regulation based on the 2 A resolution structure of scallop RD with bound Ca2+ [Houdusse A. and Cohen C. (1996) Structure 4, 21-32]. Binding of the fluorescent probe, 8-anilinonaphthalene-1-sulphonate (ANS) to the RD senses the dissociation of the regulatory light chain (RLC) in the presence of EDTA, by energy transfer from a tryptophan cluster (Trp818, 824, 826, 827) on the heavy chain (HC). We identified a hydrophobic pentapeptide (Leu836-Ala840) at the head-rod junction which is required for the effective energy transfer and conceivably is part of the ANS-binding site. Extension of the HC component of RD towards the rod region results in a larger ANS response, presumably indicating changes in HC-RLC interactions, which might be crucial for the regulatory function of scallop myosin.  (+info)

Conformational intermediates and fusion activity of influenza virus hemagglutinin. (5/531)

Three strains of influenza virus (H1, H2, and H3) exhibited similar characteristics in the ability of their hemagglutinin (HA) to induce membrane fusion, but the HAs differed in their susceptibility to inactivation. The extent of inactivation depended on the pH of preincubation and was lowest for A/Japan (H2 subtype), in agreement with previous studies (A. Puri, F. Booy, R. W. Doms, J. M. White, and R. Blumenthal, J. Virol. 64:3824-3832, 1990). While significant inactivation of X31 (H3 subtype) was observed at 37 degrees C at pH values corresponding to the maximum of fusion (about pH 5.0), no inactivation was seen at preincubation pH values 0.2 to 0.4 pH units higher. Surprisingly, low-pH preincubation under those conditions enhanced the fusion rates and extents of A/Japan as well as those of X31. For A/PR 8/34 (H1 subtype), neither a shift of the pH (to >5.0) nor a decrease of the temperature to 20 degrees C was sufficient to prevent inactivation. We provide evidence that the activated HA is a conformational intermediate distinct from the native structure and from the final structure associated with the conformational change of HA, which is implicated by the high-resolution structure of the soluble trimeric fragment TBHA2 (P. A. Bullough, F. M. Hughson, J. J. Skehel, and D. C. Wiley, Nature 371:37-43, 1994).  (+info)

Role of regulatory exosite I in binding of thrombin to human factor V, factor Va, factor Va subunits, and activation fragments. (6/531)

The blood coagulation proteinase, thrombin, converts factor V into factor Va through a multistep activation pathway that is regulated by interactions with thrombin exosites. Thrombin exosite interactions with human factor V and its activation products were quantitatively characterized in equilibrium binding studies based on fluorescence changes of thrombin covalently labeled with 2-anilinonaphthalene-6-sulfonic acid (ANS) linked to the catalytic site histidine residue by Nalpha-[(acetylthio)acetyl]-D-Phe-Pro-Arg-CH2Cl ([ANS]FPR-thrombin). Exosite I was shown to play a predominant role in the binding of factor V and factor Va from the effect of the exosite I-specific ligand, hirudin54-65, on the interactions. Factor V and factor Va bound to exosite I of [ANS]FPR-thrombin with similar dissociation constants of 3.4 +/- 1.3 and 1.1 +/- 0.4 microM and fluorescence enhancements of 182 +/- 41 and 127 +/- 17%, respectively. Native thrombin and labeled thrombin bound with similar affinity to factor Va. Among factor V activation products, the factor Va heavy chain was shown to contain the site of exosite I binding, whereas exosite I-independent, lower affinity interactions were observed for activation fragments E and C1, and no detectable binding was observed for the factor Va light chain. The results support the conclusion that the factor V activation pathway is initiated by exosite I-mediated binding of thrombin to a site in the heavy chain region of factor V that facilitates the initial cleavage at Arg709 to generate the heavy chain of factor Va. The results further suggest that binding of thrombin through exosite I to factor V activation intermediates may regulate their conversion to factor Va and that similar binding of thrombin to the factor Va produced may reflect a mode of interaction involved in the regulation of prothrombin activation.  (+info)

The membrane topology of proton-pumping Escherichia coli transhydrogenase determined by cysteine labeling. (7/531)

The membrane topology of proton-pumping nicotinamide-nucleotide transhydrogenase from Escherichia coli was determined by site-specific chemical labeling. A His-tagged cysteine-free transhydrogenase was used to introduce unique cysteines in positions corresponding to potential membrane loops. The cysteines were reacted with fluorescent reagents, fluorescein 5-maleimide or 2-[(4'-maleimidyl)anilino]naphthalene-6-sulfonic acid, in both intact cells and inside-out vesicles. Labeled transhydrogenase was purified with a small-scale procedure using a metal affinity resin, and the amount of labeling was measured as fluorescence on UV-illuminated acrylamide gels. The difference in labeling between intact cells and inside-out vesicles was used to discriminate between a periplasmic and a cytosolic location of the residues. The membrane region was found to be composed of 13 helices (four in the alpha-subunit and nine in the beta-subunit), with the C terminus of the alpha-subunit and the N terminus of the beta-subunit facing the cytosolic and periplasmic sides, respectively. These results differ from previous models with regard to both number of helices and the relative location and orientation of certain helices. This study constitutes the first in which all transmembrane segments of transhydrogenase have been experimentally determined and provides an explanation for the different topologies of the mitochondrial and E. coli transhydrogenases.  (+info)

Evidence of heterogeneous 1-anilinonaphthalene-8-sulfonate binding to beta-lactoglobulin from fluorescence spectroscopy. (8/531)

Steady-state and dynamic fluorescence titrations show that: (a) the complex between beta-lactoglobulin (BLG) and 1-anilinonaphthalene-8-sulfonate (ANS) displays a heterogeneous equilibrium with large changes in the binding strength vs. pH and ion concentration; and (b) the fluorescence response of bound ANS reveals two separate lifetimes that suggest two different sites (or binding modes). While steady-state fluorescence titrations yield effective values of the binding constant and of the bound ANS quantum efficiency, it is shown that, by combining steady-state fluorescence and lifetime decay of ANS, it is possible to give quantitative estimates of the association constants for each site. When heading from the acid (pH approximately 2) to the native state (pH approximately 6) the main result is a very large reduction of the effective binding constant. This and the results of titrations vs. ionic strength suggest that electrostatic interactions are a major contribution to ANS binding to BLG.  (+info)

Naphthalenesulfonates are a group of chemical compounds that consist of a naphthalene ring, which is a bicyclic aromatic hydrocarbon, substituted with one or more sulfonate groups. Sulfonates are salts or esters of sulfuric acid. Naphthalenesulfonates are commonly used as detergents, dyes, and research chemicals.

In the medical field, naphthalenesulfonates may be used in diagnostic tests to detect certain enzyme activities or metabolic disorders. For example, 1-naphthyl sulfate is a substrate for the enzyme arylsulfatase A, which is deficient in individuals with the genetic disorder metachromatic leukodystrophy. By measuring the activity of this enzyme using 1-naphthyl sulfate as a substrate, doctors can diagnose or monitor the progression of this disease.

It's worth noting that some naphthalenesulfonates have been found to have potential health hazards and environmental concerns. For instance, sodium naphthalenesulfonate has been classified as a possible human carcinogen by the International Agency for Research on Cancer (IARC). Therefore, their use should be handled with caution and in accordance with established safety protocols.

Anilino Naphthalenesulfonates are a group of compounds that contain both aniline and naphthalene sulfonate components. Aniline is a organic compound with the formula C6H5NH2, and naphthalene sulfonate is the sodium salt of naphthalene-1,5-disulfonic acid.

Anilino Naphthalenesulfonates are commonly used as fluorescent dyes in various applications such as histology, microscopy, and flow cytometry. These compounds exhibit strong fluorescence under ultraviolet light and can be used to label and visualize specific structures or molecules of interest. Examples of Anilino Naphthalenesulfonates include Propidium Iodide, Acridine Orange, and Hoechst 33258.

It is important to note that while these compounds are widely used in research and diagnostic settings, they may also have potential hazards and should be handled with appropriate safety precautions.

Thiosulfate Sulfurtransferase (TST) is an enzyme that catalyzes the transfer of a sulfur group from thiosulfate to a range of acceptor molecules. It plays a crucial role in the detoxification of harmful substances and the maintenance of cellular redox balance. TST is also known as Rhodanese, which comes from the Greek word "rhodanos," meaning rose-red, due to the pinkish-red color of the enzyme when it was first isolated.

The systematic medical definition of Thiosulfate Sulfurtransferase is:

A mitochondrial matrix enzyme (EC 2.8.1.1) that catalyzes the transfer of a sulfur atom from thiosulfate to cyanide, forming thiocyanate and sulfite. This reaction serves as a detoxification pathway for cyanide in the body. TST also plays a role in maintaining cellular redox balance by participating in the reduction of oxidized proteins and other molecules.

Fluorescence spectrometry is a type of analytical technique used to investigate the fluorescent properties of a sample. It involves the measurement of the intensity of light emitted by a substance when it absorbs light at a specific wavelength and then re-emits it at a longer wavelength. This process, known as fluorescence, occurs because the absorbed energy excites electrons in the molecules of the substance to higher energy states, and when these electrons return to their ground state, they release the excess energy as light.

Fluorescence spectrometry typically measures the emission spectrum of a sample, which is a plot of the intensity of emitted light versus the wavelength of emission. This technique can be used to identify and quantify the presence of specific fluorescent molecules in a sample, as well as to study their photophysical properties.

Fluorescence spectrometry has many applications in fields such as biochemistry, environmental science, and materials science. For example, it can be used to detect and measure the concentration of pollutants in water samples, to analyze the composition of complex biological mixtures, or to study the properties of fluorescent nanomaterials.

Protein denaturation is a process in which the native structure of a protein is altered, leading to loss of its biological activity. This can be caused by various factors such as changes in temperature, pH, or exposure to chemicals or radiation. The three-dimensional shape of a protein is crucial for its function, and denaturation causes the protein to lose this shape, resulting in impaired or complete loss of function. Denaturation is often irreversible and can lead to the aggregation of proteins, which can have negative effects on cellular function and can contribute to diseases such as Alzheimer's and Parkinson's.

Fluorescent dyes are substances that emit light upon excitation by absorbing light of a shorter wavelength. In a medical context, these dyes are often used in various diagnostic tests and procedures to highlight or mark certain structures or substances within the body. For example, fluorescent dyes may be used in imaging techniques such as fluorescence microscopy or fluorescence angiography to help visualize cells, tissues, or blood vessels. These dyes can also be used in flow cytometry to identify and sort specific types of cells. The choice of fluorescent dye depends on the specific application and the desired properties, such as excitation and emission spectra, quantum yield, and photostability.

Protein conformation refers to the specific three-dimensional shape that a protein molecule assumes due to the spatial arrangement of its constituent amino acid residues and their associated chemical groups. This complex structure is determined by several factors, including covalent bonds (disulfide bridges), hydrogen bonds, van der Waals forces, and ionic bonds, which help stabilize the protein's unique conformation.

Protein conformations can be broadly classified into two categories: primary, secondary, tertiary, and quaternary structures. The primary structure represents the linear sequence of amino acids in a polypeptide chain. The secondary structure arises from local interactions between adjacent amino acid residues, leading to the formation of recurring motifs such as α-helices and β-sheets. Tertiary structure refers to the overall three-dimensional folding pattern of a single polypeptide chain, while quaternary structure describes the spatial arrangement of multiple folded polypeptide chains (subunits) that interact to form a functional protein complex.

Understanding protein conformation is crucial for elucidating protein function, as the specific three-dimensional shape of a protein directly influences its ability to interact with other molecules, such as ligands, nucleic acids, or other proteins. Any alterations in protein conformation due to genetic mutations, environmental factors, or chemical modifications can lead to loss of function, misfolding, aggregation, and disease states like neurodegenerative disorders and cancer.

... (ANS), also called 1-anilino-8-naphthalenesulfonate, is an organic compound containing ...
... the most spectacular case being the anilino naphthalene sulfonates (ANS); the first description of the use of the fluorescence ...
... anilino naphthalenesulfonates MeSH D02.886.645.600.080.050.650.250 - congo red MeSH D02.886.645.600.080.050.650.300 - Evans ... anilino naphthalenesulfonates MeSH D02.092.146.215 - benzophenoneidum MeSH D02.092.146.271 - bromhexine MeSH D02.092.146.271. ... naphthalenesulfonates MeSH D02.886.645.600.080.050.650.012 - amaranth dye MeSH D02.886.645.600.080.050.650.025 - amido black ...
... anilino naphthalenesulfonates MeSH D04.615.638.555.300 - congo red MeSH D04.615.638.555.400 - Evans blue MeSH D04.615.638.555. ... naphthalenesulfonates MeSH D04.615.638.555.200 - amaranth dye MeSH D04.615.638.555.220 - amido black MeSH D04.615.638.555.282 ...
8-Anilinonaphthalene-1-sulfonic acid (ANS), also called 1-anilino-8-naphthalenesulfonate, is an organic compound containing ...
... and 8-anilino-1-naphthalenesulfonate fluorescence. Thioflavin T fluorescence specifically monitors amyloid fibrillation, ... whereas light scattering and 8-anilino-1-naphthalenesulfonate fluorescence monitor both amyloid fibrillation and amorphous ...
Naphthalenesulfonates Naphthalenesulfonates, Anilino use Anilino Naphthalenesulfonates Naphthalidine use 1-Naphthylamine ...
Naphthalenesulfonates Naphthalenesulfonates, Anilino use Anilino Naphthalenesulfonates Naphthalidine use 1-Naphthylamine ...
Naphthalenesulfonates Naphthalenesulfonates, Anilino use Anilino Naphthalenesulfonates Naphthalidine use 1-Naphthylamine ...
Naphthalenesulfonates Naphthalenesulfonates, Anilino use Anilino Naphthalenesulfonates Naphthalidine use 1-Naphthylamine ...
Naphthalenesulfonates Naphthalenesulfonates, Anilino use Anilino Naphthalenesulfonates Naphthalidine use 1-Naphthylamine ...
Anilino Naphthalenesulfonates / pharmacology Actions. * Search in PubMed * Search in MeSH * Add to Search ...
Ligand interaction between urokinase-type plasminogen activator and its receptor probed with 8-anilino-1-naphthalenesulfonate. ...
Anilino Naphthalenesulfonates - Preferred Concept UI. M0001218. Scope note. A class of organic compounds which contain an ... Naphthalenesulfonates, Anilino. Tree number(s):. D02.092.146.125. D02.455.426.559.847.638.555.282. D02.886.645.600.080.050. ... Clase de compuestos orgánicos que contienen un grupo anilino (fenilamino) unido a una sal o éster del ácido naftalensulfónico. ... A class of organic compounds which contain an anilino (phenylamino) group linked to a salt or ester of naphthalenesulfonic acid ...
Anilino Naphthalenesulfonates Preferred Term Term UI T002423. Date01/01/1999. LexicalTag NON. ThesaurusID NLM (1974). ... Anilino Naphthalenesulfonates Preferred Concept UI. M0001218. Registry Number. 0. Scope Note. A class of organic compounds ... Anilino Naphthalenesulfonates. Tree Number(s). D02.092.146.125. D02.455.426.559.847.638.555.282. D02.886.645.600.080.050. ... Naphthalenesulfonates [D02.455.426.559.847.638.555] * Amaranth Dye [D02.455.426.559.847.638.555.200] * Amido Black [D02.455. ...
Anilino Naphthalenesulfonates Preferred Term Term UI T002423. Date01/01/1999. LexicalTag NON. ThesaurusID NLM (1974). ... Anilino Naphthalenesulfonates Preferred Concept UI. M0001218. Registry Number. 0. Scope Note. A class of organic compounds ... Anilino Naphthalenesulfonates. Tree Number(s). D02.092.146.125. D02.455.426.559.847.638.555.282. D02.886.645.600.080.050. ... Naphthalenesulfonates [D02.455.426.559.847.638.555] * Amaranth Dye [D02.455.426.559.847.638.555.200] * Amido Black [D02.455. ...
Aniline Compounds N0000170045 Aniline Hydroxylase N0000166339 Aniline Mustard N0000167384 Anilino Naphthalenesulfonates ... N0000008200 Naphthacenes N0000007808 Naphthaleneacetic Acids N0000007809 Naphthalenes N0000007810 Naphthalenesulfonates ...
1-Anilino-8-naphthalene sulfonate (ANS) is not a desirable probe for determining the molten globule state of chymopapain. ... The molten globule (MG) state of proteins is widely detected through binding with 1-anilino-8-naphthalene sulphonate (ANS), a ... the exposed hydrophobic clusters of protein are readily bound by the nonpolar anilino-naphthalene moiety of ANS molecules which ...
D23.529.100.450.500 Anilino Naphthalenesulfonates D2.455.426.559.847.638.555.282 Animal Nutrition G6.696.116 G6.696.161 ( ... D2.455.426.559.847.638 Naphthalenesulfonates D2.455.426.559.847.638.555 Naphthols D2.455.426.559.847.638.638 Naphthoquinones ...
... quickly lost their ability to enhance the fluorescence of the probe 1-anilino-8 naphthalenesulfonate (1,8-ANS) indicating ...
... on the interaction of 1-anilino-8-naphthalene sulfonate (ANS) with phosphatidylcholine liposomes, Journal of Bioenergetics and ... anilino)furazano[ 3, 4-b ]pyrazines , ChemistrySelect, 10.1002/slct.201701674, 2:24, (7018-7023), Online publication date: 22- ...
Anilino Naphthalenesulfonates [D02.092.146.125] * Benzophenoneidum [D02.092.146.215] * Benzenaminium, 4,4-(3-oxo-1,5- ...
Anilino Naphthalenesulfonates Animal Assisted Therapy Animal Care Committees Animal Communication Animal Culling Animal ...

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