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Topic: Thioesters

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In the News (Mon 15 Jul 19)

  Flavoring foodstuffs with a thioester - United States Patent RE30,370
Regardless of the source of the thioester or thioesters, these substances should be free from any deleterious impurities which affect their suitability for use in flavors.
The quantity of thioester utilized should be sufficient to impart the desired vegetable flavor characteristic to the product, but on the other hand, the use of an excessive amount of such thioesters is not only wasteful and uneconomic, but too large a quantity unbalances the flavor of the product consumed.
The thioesters or compositions containing them can be applied during the "casing" or final spray treatment of the tobacco, or they can be applied at some earlier stage of curing or preparation.
xrint.com /patents/us/Re30370   (4695 words)

  Thioester - Wikipedia, the free encyclopedia
Thioesters are compounds resulting from the bonding of sulfur with an acyl group with the general formula R-S-CO-R'.
The thioester bond is what biochemists call a high-energy bond, equivalent to the phosphate bonds in adenosine triphosphate (ATP), which is the main supplier of energy in all living organisms.
Thioesters are involved in the synthesis of all esters, including those found in complex lipids.
en.wikipedia.org /wiki/Thioester   (414 words)

 Expressed protein ligation: Method and applications -- David et al. 271 (4): 663 -- FEBS Journal   (Site not responding. Last check: )
EPL for the synthesis of the Cys segment.
Thioesters can be obtained by fusing the protein of interest to the N-terminus of an intein, proteins with N-terminal Cys by fusing to the C-terminus of a mutated intein.
Nilsson, B.L., Kiessling, L.L. and Raines, R.T. (2000) Staudinger ligation: a peptide from a thioester and azide.
content.febsjournal.org /cgi/content/full/271/4/663   (7733 words)

 Life development in Laga
A thioester forms when a thiol or mercaptan (sulfur compounds analog to alcohols that givethe unpleasant odors to garlic, domestic natural gas and skunks), whose general form is written as an organic compound group, R, bonded with sulfur and hydrogen resulting in R-SH, joins with a carboxylic acid (R'-COOH).
Thioester are the equivalent to sulfur inorganic salts.
Thioesters are involved in the synthesis of all esters, including those found in complex lipids, peptides, fatty acids, sterols, terpenes, and others.
curriculum.calstatela.edu /courses/builders/worlds/planets01/laga/lagapages/LMICROBIO.HTM   (1078 words)

 Pyridine esters of cyclopropane-carboxylic acid   (Site not responding. Last check: )
The esters and thioesters of the present invention can be used along or in an inert carrier substance for the control of mites (Acarina) or can be used in mixture with pesticides and/or juvenile hormone analogs known in the art in order to obtain a broader spectrum of activity.
The esters and thioesters of the present invention are useful for the control of mites and ticks which are ectoparasitic on animals and birds.
Thioesters of Formula A are prepared by treating a solution of the corresponding acid or diacid in benzene with oxalyl chloride, heating for one to eight hours and then removing the benzene solvent.
www.sacnewsmonthly.com /invent/ornamental_replaceable_letter_displaying/pyridine_esters_cyclopropane-carboxylic_acid.html   (3961 words)

 Where did the first 'life' come from?
The thioester bond is what biochemists call a high-energy bond, equivalent to the phosphate bonds in adenosine triphosphate (ATP), which is the main supplier of energy in all living organisms.
Thioesters are involved in the synthesis of all esters, including those found in complex lipids.
The thioester world thus represents a hypothetical early stage in the development of life that could have provided the energetic and catalytic framework of the protometabolic set of primitive chemical reactions that led from the first building blocks of life to the RNA world and subsequently sustained the RNA world until metabolism took over.
www.holysmoke.org /cretins/life0.htm   (5102 words)

 Julian A. Peterson, Ph.D.   (Site not responding. Last check: )
Fatty diacid monoethyl thioesters are introduced as a new class of irreversible inhibitors that exploit the omega-2 oxidation specificity of cytochrome P450BM-3.
Catalytic oxidation of the monoethyl thioesters of dodecanedioic and hexadecanedioic acids results in enzyme inactivation and formation of the parent diacids as metabolites.
This finding, and the observation that glutathione prevents inactivation of the enzyme by the monoethyl thioesters, indicate that a diffusible metabolite, probably the sulfoxide, is responsible for enzyme inactivation.
www.swmed.edu /home_pages/peterlab/ref14.htm   (298 words)

 The Straight Dope: Why does asparagus make your pee smell funny?
In 1975 one Robert H. White, then with the chemistry department at the University of California at San Diego, found that the odor-causing chemical was not methanethiol after all.
Instead, using gas chromatography-mass spectrometry (Bob was obviously not one to screw around), he found that the aroma was in fact caused by several S-methyl thioesters, specifically S-methyl thioacrylate and S-methyl 3-(methylthio)thiopropionate.
(Thioesters are compounds that result from the reaction of an acid with a sulfur-containing alcohol.
www.straightdope.com /classics/a2_383.html   (540 words)

 Space Science Division
Since earlier studies by us and other investigators have indicated the involvement of amino acid and peptide thioesters in prebiotic peptide synthesis, we developed a new, very simple method for preparing peptide thioesters that involves the reaction of a thiol molecule with amino acids activated by reaction with the commercially available reagent (carbonyldiimidazole).
This synthetic method was used to prepare peptide thioesters from three and eight amino acids in length for several different amino acids.
To identify and understand the chemistry that could have been involved in the origin of the earliest replicating molecule under mild aqueous conditions, we calculated the energy values for the chemical changes that occur in carbon groups undergoing redox reactions and carbon-carbon bond cleavage reactions.
www-space.arc.nasa.gov /displaypage.cfm?page=Weber&branch=ssx   (400 words)

 Year 2002: ORGLIST: thioester mechanisms.
to be thioesters which hydrolyze at the same rate as oxygen esters.
It's usually assumed that although thioesters are thermodynamically > >unstable relative to oxygen esters, the rates of hydrolysis are similar.
Along the same lines, it is also generally stated that thioesters > >are like ketones (due to poor electronegativity of S and limited > >delocalization).
www.orglist.net /archive/2002/0038.html   (511 words)

 Native chemical ligation - Wikipedia, the free encyclopedia
In native chemical ligation a peptide containing a C-terminal thioester reacts with another peptide containing an N-terminal cysteine, in the presence of an exogenous thiol catalyst.
Peptide-thioesters to be used in native chemical ligation are usually prepared by Boc chemistry SPPS; the thioester piece cannot be synthesized with a nucleophilic base, thus disfavoring Fmoc chemistry.
Fmoc techniques for generating thioesters involving the modifications of the Kenner 'safety catch' linker are known.
en.wikipedia.org /wiki/Native_chemical_ligation   (377 words)

 Letter: Collision-induced dissociation of peptide thioesters : influence of the peptide length on the fragmentation   (Site not responding. Last check: )
Five peptide thioesters of increasing length were fragmented under two processes, in-source and in-collision cell fragmentation, using an electrospray source coupled to a triple quadrupole.
The two fragmentation conditions show that the peptide length has no influence on structural information and that the fragmentation efficiency is higher for the smallest peptides than for the longest.
The absence of the a3 fragment ion and the presence of the (a
www.impub.co.uk /abs/EMS11_0031.html   (187 words)

 Reversible Michael Reaction-Enzymatic Hydrolysis: A New Variant of Dynamic Resolution
As part of a study of new syntheses of roxifiban, we discovered that the conversion of 1 to a wide variety of thioesters 3 is efficient.
Thioesters are rarely used as substrates for enzymatic resolution, and the best choice of R was not predictable.
Another indication of a rapid enantiospecific reaction is that the ratio of (S) to (R) thioester 3b gradually increased to 7-8:1 once the reaction was ~80% complete, suggesting a significantly higher enzyme-catalyzed hydrolysis rate versus racemization rate (otherwise comparable rates would have soon equilibrated the 3b enantiomers).
pubs.acs.org /cgi-bin/jcen?jacsat/123/i44/html/ja011811l.html   (1822 words)

A thioester method and the native chemical ligation method are useful for protein synthesis.
Though both methods use peptide thioesters as building blocks, no route was known to use the thioester method after the peptide bond formation reaction by the native chemical ligation method.
In the thioester method, the SH groups of the cysteine residues have to be protected by a group that is stable in the presence of silver ions as an activator of thioester groups.
www.nig.ac.jp /labs/AnnualRp/AR2004e/55ad1.html   (1693 words)

 Studies on the Reactivity of Clofibryl-S-Acyl-CoA Thioester with Glutathione in Vitro -- Grillo and Benet 30 (1): 55 -- ...
Brophy PJ and Vance DE (1976) The synthesis and hydrolysis of long-chain fatty acyl-coenzyme A thioesters by soluble and microsomal fractions from the brain of the developing rat.
Hertz R and Bar-Tana J (1988) The acylation of proteins by xenobiotic amphipathic carboxylic acids in cultured rat hepatocytes.
Lygre T, Aarsaether N, Stensland E, Aarsland A and Berge RK (1986) Separation and measurement of clofibryl coenzyme A and clofibric acid in rat liver after clofibrate administration by reverse-phase high-performance liquid chromatography with photodiode array detection.
dmd.aspetjournals.org /cgi/content/full/30/1/55   (4808 words)

 Acyltransferase patent invention
Conversion of phospholipids into lysolipids without increased amounts of unesterified fatty acids is therefore desirable and can be achieved with acyltransferases that transfer the fatty acid from the phospholipid to an acyl acceptor such as monoacylglycerols, diacylglycerols, alcohols, or any other acyl acceptors present in or added to the raw material.
Such an improved acyltransferase can be used in a huge number of chemical reactions for the production of a large number of different fatty acid esters and/or fatty acid thioesters, which enables the possibility to in a economic way produce a large amount of a single enzyme which then can be used for several purposes.
Such an active membrane independent acyltransferase polypeptide may be used in a bioreactor for the production of desired fatty acid esters or as additive in food raw material for modification of its lipid composition without the need of a microorganism or a lipid membrane for the maintenance of the acyltransferase activity.
www.freshpatents.com /Acyltransferase-dt20060629ptan20060141457.php   (4192 words)

 Scientific Papers - W
Weber, A. (1997) Prebiotic amino acid thioester synthesis: Thiol-dependent amino acid synthesis from formose substrates (formaldehyde and glycolaldehyde) and ammonia.
Weber, A. (2004) Aqueous synthesis of peptide thioesters from amino acids and a thiol using 1, 1’-carbonyldiimidazole.
Weber, A. 2005, Aqueous Synthesis of Peptide Thioesters from Amino Acids and a Thiol Using 1, 1'-Carbonyldiimidazole, Orig.
www.seti.org /publications/weber-arthur.php   (1201 words)

 BICH303_learn_obj_TCAcycle   (Site not responding. Last check: )
PDH complex conserves the energy of pyruvate oxidation to acetate in the form of a thioester and NADH2.
CoA is a carrier of acyl (acid) functions (eg, acetate) as thioesters.
Thioesters are used because the alpha proton is labile ­ readily forms an enolate anion (negative charge on alpha-C).
www.tamu.edu /classes/bich/gunn/BICH303_learn_obj_TCAcycle.html   (503 words)

 The scientific origin of life
Analog catalysts like some co-enzymes, ribozymes and thioesters are transformed during the process of interaction.
Christian de Duve (3) has argued convincingly how the enzymatically driven metabolism of biology is functionally congruent with the prebiotic catalysis driven by for example thioesters.
Although enzymes are very different from thioesters, they fulfill the same functional role.
users.ugent.be /~mvaneech/NYAS.html   (3618 words)

 Differential regulation of cytosolic and peroxisomal bile acid amidation by PPAR{alpha} activation favors the formation ...
Chenodeoxycholoyl-CoA thioesterase activity was measured in the mitochondrial (M), light-mitochondrial (L), microsomal (P), and cytosolic (S) fractions obtained after subcellular fractionation of pooled mouse liver homogenates as described in Fig.
The binding of bile acid-CoA thioesters to FXR was examined in a coactivator recruitment assay as described in Materials and Methods.
The primary bile acid-CoA thioesters produced in the peroxisomes are either amidated by the peroxisomal BACAT or thiolytically cleaved by the peroxisomal acyl-CoA thioesterase 2 (PTE-2).
www.jlr.org /cgi/content/full/45/6/1051   (5584 words)

 e-Prints Soton - A new method of forming resin bound thioesters and their use as ‘traceless’ linkers in ...
A new method of forming resin bound thioesters and their use as ‘traceless’ linkers in solid phase synthesis
May, P. J., Bradley, M., Harrowven, D. and Pallin, D. A new method of forming resin bound thioesters and their use as ‘traceless’ linkers in solid phase synthesis.
Resin bound thioesters can be prepared by heating thioamides in aqueous DMF with Merrifield resin in the presence of sodium iodide.
eprints.soton.ac.uk /18951   (156 words)

 Optimization of unique, uncharged thioesters as inhibitors of HIV replication.
These data revealed that there was no significant correlation between thioester stability and antiviral activity, however, a slight inverse correlation between serum stability and virucidal activity was noted.
Several thioesters demonstrated potent inhibition of HIV cell-to-cell transmission with EC50 values in the 80-100 nM range.
Thus, we have optimized a series of restricted thioesters and provided evidence that serum stability is not required for antiviral activity.
hiv.researchtoday.net /archive/1/4/1719.htm   (313 words)

 Chromogenic substrates   (Site not responding. Last check: )
The rate of thioester hydrolysis is then measured at 324 nanometers to monitor the formation of 4-thiopyridone (E
These extinction molar coefficients allow to calculate the original concentration of the thioester substrate after total hydrolysis of this substrate.
Arginine and Lysine containing substrates may be used to detect serine protease activites in crude homogenates.
delphi.phys.univ-tours.fr /Prolysis/chromo.html   (297 words)

 Long-Chain Acyl-CoA-Dependent Regulation of Gene Expression in Bacteria, Yeast and Mammals -- Black et al. 130 (2): 305 ...
Fatty acyl-CoA thioesters are essential intermediates in lipid metabolism.
Upon entry it is either bound to fatty acid binding protein (FABP) for intracellular transport or it is activated to the CoA thioester.
and operons is inhibited by long-chain acyl-coenzyme A thioesters
jn.nutrition.org /cgi/content/full/130/2/305S   (4107 words)

 Current Organic Chemistry Volume 5, Number 1, 2001
All the current ligation methods that produce a native peptide bond use peptide C-terminal thiocarboxylic acids or thioesters as building blocks.
Based on this approach, a thioester method was developed, in which partially protected peptide thioesters are used as building blocks.
Subsequently, a new ligation method was developed using peptide thioesters, in which protecting group is no longer necessary.
www.bentham.org /coc/contabs/coc5-1.htm   (617 words)

 Home Page
For polyolefins containing a standard hindered phenol/phosphite formulation plus a thioester (added for long term thermal stability), there is often a long induction time when no apparent changes are seen in either appearance or physical properties.
A common problem with this technique, however, is that the degradation mechanism at elevated temperatures may be different from the mechanism at lower temperatures.
This is particularly true if hindered amine light stabilizers (HALS) are being compared to thioesters such as DSTDP for their effectiveness as long term heat stabilizers.
polymersales.com /technical/index.html   (807 words)

 Modulation by nutrients and drugs of liver acyl-CoAs analyzed by mass spectrometry -- Kalderon et al. 43 (7): 1125 -- ...
Fatty acyl-CoA thioesters are ligands of hepatic nuclear factor-4
Fatty acyl-CoA thioesters inhibit recruitment of steroid receptor co-activator 1 to alpha and gamma isoforms of peroxisome-proliferator-activated receptors by competing with agonists.
Analysis of long chain fatty acyl coenzyme A thioesters by negative ion fast-atom bombardment mass spectrometry and tandem mass spectrometry.
www.jlr.org /cgi/content/full/43/7/1125   (3069 words)

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