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Topic: Thiol group


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  Thiol   (Site not responding. Last check: 2007-11-03)
In chemistry, thiols (formerly known as mercaptans) are those compounds which contain the sulfhydryl group -SH attached to a carbon atom.
Thiols are similar to alcohols, with the oxygen of the hydroxyl group -OH being replaced by a sulfur atom.
Thiols bind strongly to skin proteins, and are responsible for the intolerable, persistent odor produced by the spraying of skunks.
thiol.iqnaut.net   (237 words)

  
 Thiol - Wikipedia, the free encyclopedia
The thiol group is the sulfur analog of the hydroxyl group (-OH) found in alcohols.
The chemistry of thiols is thus related to the chemistry of alcohols: thiols form thioethers, thioacetals and thioesters, which are analogous to ethers, acetals, and esters.
Thiols bind strongly to skin proteins, and are responsible for the intolerable, persistent odor produced by feces, rotting flesh and the spraying of skunks.
en.wikipedia.org /wiki/Thiol   (782 words)

  
 U.S. Patent: 5155173 - Fluorine-containing copolymer, process for its production and curable composition - October 13, ...
In the third method, the reactive group in the fluoride-containing copolymer Y may be a hydroxyl group, a carboxylic acid, group, an amino group, an acid amide group, a thiol group, an active halogen-containing group, an epoxy group or an ethylenically unsaturated group.
Among the fluorine-containing copolymers of the present invention, one having an active hydrogen-containing group or an epoxy group at the terminal of the polyoxyalkylene chain (hereinafter referred to as a fluorine-containing copolymer (a)) ma be combined with a curing agent to obtain a curable composition (hereinafter referred to as a composition (a)).
In this case, from the viewpoint of the reactivity with an isocyanate group, it is particularly preferred to employ as the fluorine-containing copolymer (a) a copolymer having an active hydrogen-containing group, particularly, a hydroxyl group.
www.everypatent.com /comp/pat5155173.html   (6336 words)

  
 Polymer having thiol end group - Patent 4565854
A polymer having a thiol group at one end obtained by polymerizing at least one monomer capable of radical polymerization in contact with a thiolcarboxylic acid represented by the formula R--COSH wherein R is a C.sub.1 -C.sub.18 aliphatic or aromatic hydrocarbon group; and then treating the resulting polymer wtih an alkali or acid.
The polymer having a thiol group at one end as set forth in claim 1, wherein said monomer capable of radical polymerization is selected from the group consisting of a vinyl ester, a vinyl halide, an aromatic vinyl compound, an.alpha.-olefin, acrylic acid, methacrylic acid, acrylic ester, methacrylic ester, acrylamide, methacrylamide, acrylonitrile and methacrylonitrile.
The quantity of the thiol group was 9.99.times.10.sup.-5 eq/q as determined by iodimetry in acetone/water.
www.freepatentsonline.com /4565854.html   (10174 words)

  
 Modified pigments and process for preparing modified pigments - Patent 6833026
Preferably, the electrophilic group is an.alpha.,.beta.-unsaturated ketone, aldehyde, or sulfone group or an alkylsulfate group or salt thereof.
For example, it is preferred that the pigment and thiol reagent are combined under alkaline conditions, which form the thiolate and may assist in the reaction of the thiol reagent with the pigment.
The --SH group may be present along the backbone of the thiopolymer, such as, for example, as part of a pendant group, or as a terminating group on the end(s) of the polymer.
www.freepatentsonline.com /6833026.html   (6105 words)

  
 Thiol Functional Group | World of Chemistry
Thiols are molecules which contain an SH group.
Thiols tend to be a clear liquid or white crystalline form.
Thiols are also found naturally in garlic, onions, coffee, and skunk secretions.
www.bookrags.com /research/thiol-functional-group-woc   (217 words)

  
 cysteine - HighBeam Encyclopedia
Cysteine's importance is related to the presence of a sulfur-containing thiol group in its side chain.
This group participates in the catalytic reactions of certain enzymes, such as that of papain, the enzyme from papaya latex used to make commercial meat tenderizers.
The thiol group of one cysteine residue is capable of combining with the thiol group of another to form a disulfide bridge, either linking two peptide chains together, as in the case of insulin, or causing a single peptide chain to fold back on itself, making a loop.
www.encyclopedia.com /doc/1E1-cysteine.html   (457 words)

  
 eMedicine - Pemphigus, Drug-Induced : Article Excerpt by: Diane M Scott, MD   (Site not responding. Last check: 2007-11-03)
Thiol drugs may interfere with critical enzymes, such as keratinocyte transglutaminase, resulting in loss of epidermal cell cohesion.
Thiol drugs may activate endogenous proteolytic enzymes, such as plasminogen activators, with subsequent cleavage of desmosomal antigens.
An active amide group is found in the structure of many nonthiol drugs, which has resulted in the speculation that this structure may be responsible for the induction of disease.
www.emedicine.com /derm/byname/pemphigus-drug-induced.htm   (582 words)

  
 U.S. Patent: 6004531 - Metal chelating compounds having an SNNN donor set - December 21, 1999
The thiol protecting group Z may be trityl, benzoyl, tetrahydropyran, benzyl, acetamidomethyl, or the corresponding disulphide dimer or others well known in the art.
In these compounds, a metal chelating moiety is joined to a targeting group by means of a linking group, which preferably comprises a chain from 1 to 12 atoms long, in which hetero atoms such as S, N and O are possible, as also are amide and ester linkages.
A group R that represents a targeting group or a peptide reactive functionality, together with any linking group present, is not subject to the C.sub.1 -C.sub.20 size limitation and other features of the other R's.
www.everypatent.com /comp/pat6004531.html   (10260 words)

  
 [No title]   (Site not responding. Last check: 2007-11-03)
In the presence of other thiol groups or other cysteine amino acids in the protein chains, oxidation can occur forming a disulfide bond.
Extracellular proteins generally have thiols in the form of intramolecular disulfide bonds between the cysteines of the protein.
When working with intracellular proteins containing free thiol groups, a reducing environment that mimics the cell’s interior is necessary.
www.revco-sci.com /documents/protstb2.doc   (1093 words)

  
 Srinivas, Mol Vis 2005; 11:249-255.   (Site not responding. Last check: 2007-11-03)
Changes in the accessibility of the thiol group near the end of the α-crystallin domain in the absence and the presence of arginine hydrochloride were studied using dithiobisnitrobenzoic acid.
Fractional accessibility of the thiol groups was calculated using the molar extinction coefficient of 14150 at 412 nm [37].
Only a fraction of the thiol groups in the oligomeric assembly of α-crystallin is accessible to thiol-modifying reagents and the accessible fraction increases upon perturbing the assembly by denaturants or the pH of the medium [44,45].
www.molvis.org /molvis/v11/a29   (4325 words)

  
 LABPV Newsletter issue 13   (Site not responding. Last check: 2007-11-03)
This process is called "thiol pumping" and results in the formation of the parent molecule and the thiyl free radical, or a radical derived therefrom (3).
The sulfhydryl group of cysteine is important to both the structure and the function of proteins.These roles are modulated by the oxidation of L-cysteine.
Since 1946 thiols are known to function as substrates for peroxidases acting as potential electron donors of the intermediates compound I and II (24-36).
www.unige.ch /LABPV/newsletters/newsl13/n13p83.html   (3704 words)

  
 Using Thiol-Modified Oligos
Two types of reagents can be used to introduce a thiol group at the 5' end of an oligonucleotide: the 5'-Thiol-Modifier-C6 and the 5'-Thiol Modifier C6 S-S (Disulfide).
Modified oligos terminated with the 5'-Thiol-Modifier C6 are shipped with the trityl protecting group still attached to the sulfur.
In order to free the thiol group for use, remove the trityl group and reduce the sulfur.
www.oligos.com /thiolModified.htm   (347 words)

  
 thiol - HighBeam Encyclopedia   (Site not responding. Last check: 2007-11-03)
Potentiation of limulin-mediated cytolysis by thiol ester-reacted forms of limulus alpha2-macroglobulin: identification of functionally important domains.
The plasma-based cytolytic system of the American horseshoe crab, Limulus polyphemus: cooperative interaction of the sialic acid-binding lectin limulin and thiol ester-reacted alpha2-macroglobulin.
Sulfur assimilation in soybean: molecular cloning and characterization of O-acetylserine (thiol) lyase (cysteine synthase).(Genomics, Molecular Genetics & Biotechnology)
www.encyclopedia.com /doc/1E1-x-thiol.html   (199 words)

  
 Ubiquitin pathway   (Site not responding. Last check: 2007-11-03)
It is the alpha-carboxyl group of the terminal glycine which forms isopeptide bonds with target proteins (which can include another copy of ubiquitin).
The isopeptide bond is formed with an (epsilon) amino group in the side chain of a lysine residue of the target protein.
This is followed by transfer of ubiquitin to the acive site cysteine of E1 to form a thiol ester between the C-terminus of ubiquitin and the thiol group of the E1.
www.nottingham.ac.uk /biochemcourses/students/ub/ubpath.html   (684 words)

  
 Silverman Lab, Dept. of Chemistry, University of Illinois at Urbana-Champaign
The special chemical reactivity of primary amino groups and thiol groups compared to all of the functional groups naturally present in nucleic acids permits us to derivatize RNA in ways that would be impossible without the use of organic synthesis to enable such experiments.
When the attacking nucleophile is a 5'-hydroxyl group, we have consistently observed formation of the non-native 2'-5' linkage instead of the native 3'-5' linkage.
Subsequently, the sulfhydryl group of the cysteine residue is covalently linked via a disulfide to an oligonucleotide with a 3'-tethered thiol group.
www.scs.uiuc.edu /~scott/synthesis.html   (1230 words)

  
 Organosulfur compounds - Wikipedia, the free encyclopedia
Sulfur shares the chalcogen group with oxygen, and it is expected that organosulfur compounds have similarities with carbon-oxygen compounds, which is true to some extent.
Thiols are structurally similar to the alcohol group, but these functionalities are very different in their chemical properties.
The diffence in electronegativity between sulfur (2.58) and hydrogen (2.20) is small and therefore hydrogen bonding in thiols is not prominent.
en.wikipedia.org /wiki/Organosulfur_compounds   (1062 words)

  
 Inhibition of Papain by S-Nitrosothiols. FORMATION OF MIXED DISULFIDES -- Xian et al. 275 (27): 20467 -- Journal of ...
in 85% yield by nitrosation of the free sulfhydryl group with
The free thiol group of the protein was titrated by 5-(octyldithio)-2-nitrobenzoate as described by Faulstich et al.
the concentration of the free thiol in papain was 8.5 µ
www.jbc.org /cgi/content/full/275/27/20467   (4701 words)

  
 Oligos Etc.
Carboxy-dT:   Carboxy-dT can be used in place of a dT in an internal position of the oligo, or as the 5' terminal base.  The carboxy-dT modifier allows direct coupling of an oligo to a molecule or surface with a primary amine.  This modifier is added to the oligo on the machine during synthesis.
Thiol Modifiers: There are two thiol modifiers available for coupling to an oligo, a C6-disulfide (C6 S-S) and a C6-thiol modifier (C6 S-H).
Internal Thiol Modifiers:  There are three modifiers that can be used to introduce a thiol group internal to the oligonucleotide.  They are 6-Thio-dG, 4-Thio-dT, and 4-Thio-dU.
www.oligosetc.com /modifier_descriptions.php   (789 words)

  
 UM Chemistry
Thiol metabolites also play direct roles in drug modification and elimination and, in doing so, contribute to the growing problem of antibiotic resistance among pathogenic bacteria.
Among these, the thiol and the disulfide oxidation states are best known, but modifications such as sulfenic (Cys-SOH), sulfinic (Cys-SO H), and sulfonic acids (Cys-SO H) are increasingly found to play important roles in catalysis, detoxification and as sensors of oxidative stress.
A natural corollary of this project will be to investigate the catalytic mechanism of enzymes known to be involved in the reduction of oxidized thiols as well as to discover new catalysts responsible for the recycling of protein cysteines to their reduced state.
www.umich.edu /~michchem/faculty/carrollK   (833 words)

  
 Practical and Scaleable Syntheses of 3-Hydroxythiophenol - [www.rhodium.ws]
Nucleophilic displacement of the diazonium group with a sulfur nucleophile readily yields the thiol.
The second approach is to start from a precursor containing an aryl thiol group and a second functional group that can be converted readily to a phenolic hydroxyl function.
The success of this approach is hinged on the protection of the thiol group prior to the diazonium salt formation, to avoid its potentially hazardous reaction with the diazonium salt.
www.erowid.org /archive/rhodium/chemistry/3-hydroxythiophenol.html   (2974 words)

  
 Kate S. Carroll - Research Interests   (Site not responding. Last check: 2007-11-03)
Among the functionalities found in nature, the thiol group (R-SH) is endowed with remarkable chemical reactivity.
Enzymes involved in the biosynthesis and recycling of these thiols will also be targeted for discovery and biochemical investigation.
In proteins, eukaryotes and prokaryotes alike incorporate the thiol functional group in the context of the amino acid cysteine where it plays pivotal roles in metal binding and catalysis.
www.cchem.berkeley.edu /~crbgrp/carroll.htm   (475 words)

  
 Immobilization of Nucleic Acids at Solid Surfaces: Effect of Oligonucleotide Length on Layer Assembly -- Steel et al. ...
5' hexanethiol anchoring group with that of unfunctionalized oligonucleotides
Due to the presence of the thiol group, the behavior of thiolated probes is expected to be more complicated.
Synthesis and characterization of DNA with ferrocenyl groups attached to their 5'-termini: electrochemical characterization of a redox-active nucleotide monolayer.
www.biophysj.org /cgi/content/full/79/2/975   (4734 words)

  
 GST - MEETING 1997 - P9   (Site not responding. Last check: 2007-11-03)
The mechanism is also thought to involve enzymatic activation of the glutathione thiol group by a hydroxyl group near to the N-terminus of the protein.
This hydroxyl group has been shown to have an unusually low pKa value and this is thought to affect the thiol of glutathione either directly or indirectly though a water molecule, leading to thiol activation.
The enzyme was produced recombinantly, enabling the proportion of stable isotopes incorporated in the protein to be altered such that the protein can be labelled by amino acid type with NMR sensitive nuclei, facilitating analysis.
www.unich.it /GST97/P9.htm   (393 words)

  
 Search ScienceWorld
Name the compound as a hydrocarbon, changing the -e ending to -oic and adding the word acid.
(2) Number the carbon atoms so that the number for the hydroxy group is as low as possible.
Select the longest chain containing the thiol group.
scienceworld.wolfram.com /search/index.cgi?as_q=Chain+compound   (414 words)

  
 Thiol Protein Defect in Sodium-Lithium Countertransport in Subset of Essential Hypertension -- Mead et al. 34 (6): 1275 ...
Thus, a thiol protein is strongly implicated in the abnormality,
to the thiol alkylation with NEM in the presence of sodium or
that the thiol group that reacts rapidly with NEM in the absence
hyper.ahajournals.org /cgi/content/full/34/6/1275   (3550 words)

  
 Merck KGaA - Coupling on SH beads -
Reactive groups able to couple with thiol contained in molecules (or coated onto the surface of the microspheres) are frequently used on cross-linking, especially in the design of heterobifunctional cross-linkers where sulfhydryl-reactive groups are present on one of two ends.
Many of the reactive groups involved in these reactions are stable in aqueous environment and allow a two-step conjugation strategy.
Main functional groups involved in reactions with Thiol to create sulfhydryl-reactive compounds are Haloacetyls and Maleimides.
www.merck.de /servlet/PB/menu/1320090/index.html   (816 words)

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