scholarly journals Peptide formation as on the early Earth: from amino acid mixtures to peptides in sulphur dioxide

2021 ◽  
Author(s):  
Oliver Trapp ◽  
Fabian Sauer ◽  
Maren Haas ◽  
Constanze Sydow ◽  
Alexander Siegle ◽  
...  
Keyword(s):  
Amino Acids ◽  
Sulphur Dioxide ◽  
Room Temperature ◽  
Early Earth ◽  
Peptide Bonds ◽  
Metal Catalysis ◽  
Peptide Formation ◽  
Liquid Sulphur ◽  
Catalytically Active ◽  
Amino Acid Mixtures

Abstract The formation of peptide bonds is one of the most important biochemical reaction steps. Without the development of structurally and catalytically active polymers, there would be no life on our planet. Intensive research is being conducted on possible reaction pathways for the formation of complex peptides on the early Earth. Salt-induced peptide formation (SIPF) by metal catalysis is one possible pathway for abiotic peptide synthesis. The high salt concentration supports dehydration in this process. However, the formation of large, complex oligomer systems is prevented by the high thermodynamic barrier of peptide condensation in aqueous solution. Liquid sulphur dioxide proves to be a superior alternative for copper-catalysed peptide condensation. Compared to water, the amino acids are activated in sulphur dioxide, which leads to the incorporation of all 20 proteinogenic amino acids into the resulting proteins and thus to a large variety of products. Strikingly, even extremely low initial reactant concentrations of only 50 mM are sufficient for extensive peptide formation, leading to an overall yield of 2.9% for dialanine in 7 days. The reactions carried out at room temperature and the successful use of the Hadean mineral covellite as a catalyst, suggest a volcanic environment for the formation of the peptide world on early Earth as a likely scenario.

scholarly journals From amino acid mixtures to peptides in liquid sulphur dioxide on early Earth

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Fabian Sauer ◽  
Maren Haas ◽  
Constanze Sydow ◽  
Alexander F. Siegle ◽  
Christoph A. Lauer ◽  
...  
Keyword(s):  
Amino Acids ◽  
Sulphur Dioxide ◽  
Room Temperature ◽  
Early Earth ◽  
Peptide Bonds ◽  
Initial Reactant ◽  
Peptide Formation ◽  
Liquid Sulphur ◽  
Catalytically Active ◽  
Amino Acid Mixtures

AbstractThe formation of peptide bonds is one of the most important biochemical reaction steps. Without the development of structurally and catalytically active polymers, there would be no life on our planet. However, the formation of large, complex oligomer systems is prevented by the high thermodynamic barrier of peptide condensation in aqueous solution. Liquid sulphur dioxide proves to be a superior alternative for copper-catalyzed peptide condensations. Compared to water, amino acids are activated in sulphur dioxide, leading to the incorporation of all 20 proteinogenic amino acids into proteins. Strikingly, even extremely low initial reactant concentrations of only 50 mM are sufficient for extensive peptide formation, yielding up to 2.9% of dialanine in 7 days. The reactions carried out at room temperature and the successful use of the Hadean mineral covellite (CuS) as a catalyst, suggest a volcanic environment for the formation of the peptide world on early Earth.

scholarly journals Solid Phase Peptide Synthesis by Four Component Condensation: Peptide Formation on an Isocyano Polymer Support

1981 ◽  
Vol 36 (9) ◽  
pp. 1202-1203 ◽  
Author(s):  
Reza Arshady ◽  
Ivar Ugi
Keyword(s):  
Amino Acids ◽  
Peptide Synthesis ◽  
Trifluoroacetic Acid ◽  
Room Temperature ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Polymer Support ◽  
Small Peptides ◽  
Peptide Formation

Abstract Coupling of various protected amino acids or small peptides on an isocyano polymer and in the presence of 1 -methyl-3-formylindole demonstrates the feasibility of peptide formation by four component condensation on a polymer support, and the final peptide is detached from the resin by 50% trifluoroacetic acid in aceto-nitrile at room temperature.

Organomercury compounds. IX. Preparations, structures, and thermal decomposition of arylmercuric arenesulphinates

1969 ◽  
Vol 22 (3) ◽  
pp. 549 ◽  
Author(s):  
GB Deacon ◽  
PW Felder
Keyword(s):  
Thermal Decomposition ◽  
Solid State ◽  
Sulphur Dioxide ◽  
Room Temperature ◽  
The Other ◽  
Linkage Isomers ◽  
Liquid Sulphur ◽  
Organomercury Compounds ◽  
Cold Acetone

The arylmercuric arenesulphinates, PhHg(SO2Ph), p-MeC6H4Hg(SO2-p-MeC6H4), PhHg(SO2-p-MeC6H4), p-MeC6H4Hg(SO2Ph), and C6F5Hg(SO2Ph), have been prepared by reaction of mercuric benzenesulphinate or p- toluenesulphinate with the appropriate diarylmercury compound in chloroform or methanol, and the first three compounds have also been obtained by reaction of liquid sulphur dioxide with diphenylmercury, di-p-tolylmercury, or phenyl-p-tolylmercury. Linkage isomers of phenylmercuric benzenesulphinate have been prepared. Isomer A, obtained from chloroform-pentane, is considered to be a monomeric O-sulphinato complex, and isomer B, obtained from cold acetone, methyl ethyI ketone, or methanol, to be an S-sulphinato complex. The isomers are readily interconverted. In chloroform, deuterochloroform, and acetone, at room temperature, only the O-sulphinato complex can be detected. The other arylmercuric arenesulphinates have the same structure as isomer A. Linkage isomers could not be isolated for these derivatives. However, there is evidence that p-MeC6H4Hg(SO2Ph) slowly isomerizes in the solid state to give the corresponding S-sulphinato complex. Thermal decomposition of PhHg-(SO2Ph) (both isomers), p-MeC6H4Hg(SO2-p-MeC6H4), PhHg(SO2-p-MeC6H4), and p-MeC8H4Hg(SO2Ph) gives sulphur dioxide and the corresponding diarylmercurycompound.

Sewage sludge as a precursor of adsorbents/catalysts for environmental applications

2007 ◽  
Vol 2 (1) ◽  
Author(s):  
A. Ros ◽  
C. Canals-Batlle ◽  
M.A. Lillo-Ródenas ◽  
E. Fuente ◽  
M. A. Montes-Morán ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Room Temperature ◽  
Waste Water Treatment ◽  
Textural Properties ◽  
Active Species ◽  
Elemental Sulphur ◽  
Gaseous Emissions ◽  
Removal Experiments ◽  
Catalytically Active

This paper focuses on the valorisation of solid residues obtained from the thermal treatment of sewage sludge. In particular, sewage sludge samples were collected from two waste water treatment plants (WWTPs) with different sludge line basic operations. After drying, sludges were heated up to 700 °C in appropriate ovens under diluted air (gasification) and inert (pyrolysis) atmospheres. The solids obtained, as well as the dried (raw) sludges, were characterised to determine their textural properties and chemical composition, including the speciation of their inorganic fraction. All the materials under study were employed as adsorbents/catalysts in H2S removal experiments at room temperature. It was found that, depending on the particular sludge characteristics, outstanding results can be achieved both in terms of retention capacities and selectivity. Some of the solids outperform commercially available sorbents specially designed for gaseous emissions control. In these adsorbents/catalysts, H2S is selectively oxidised to elemental sulphur most likely due to the presence of inorganic, catalytically active species. The role of the carbon-enriched part on these solids is also remarked.

Antimyotoxic Activity of Synthetic Peptides Derived from Bothrops atrox Snake Gamma Phospholipase A2 Inhibitor Selected by Virtual Screening

2019 ◽  
Vol 19 (22) ◽  
pp. 1952-1961 ◽  
Author(s):  
J.C. Sobrinho ◽  
A.F. Francisco ◽  
R. Simões-Silva ◽  
A.M. Kayano ◽  
J.J. Alfonso Ruiz Diaz ◽  
...  
Keyword(s):  
Amino Acids ◽  
Molecular Docking ◽  
Synthetic Peptides ◽  
Cell Damage ◽  
Neutralization Assay ◽  
Phospholipase Activity ◽  
Phospholipases A2 ◽  
Catalytically Active ◽  
Bothrops Atrox

Background: Several studies have aimed to identify molecules that inhibit the toxic actions of snake venom phospholipases A2 (PLA2s). Studies carried out with PLA2 inhibitors (PLIs) have been shown to be efficient in this assignment. Objective: This work aimed to analyze the interaction of peptides derived from Bothrops atrox PLIγ (atPLIγ) with a PLA2 and to evaluate the ability of these peptides to reduce phospholipase and myotoxic activities. Methods: Peptides were subjected to molecular docking with a homologous Lys49 PLA2 from B. atrox venom modeled by homology. Phospholipase activity neutralization assay was performed with BthTX-II and different ratios of the peptides. A catalytically active and an inactive PLA2 were purified from the B. atrox venom and used together in the in vitro myotoxic activity neutralization experiments with the peptides. Results: The peptides interacted with amino acids near the PLA2 hydrophobic channel and the loop that would be bound to calcium in Asp49 PLA2. They were able to reduce phospholipase activity and peptides DFCHNV and ATHEE reached the highest reduction levels, being these two peptides the best that also interacted in the in silico experiments. The peptides reduced the myotubes cell damage with a highlight for the DFCHNV peptide, which reduced by about 65%. It has been suggested that myotoxic activity reduction is related to the sites occupied in the PLA2 structure, which could corroborate the results observed in molecular docking. Conclusion: This study should contribute to the investigation of the potential of PLIs to inhibit the toxic effects of PLA2s.

Effects of Amino Acids on Phosphate Adsorption Onto Iron (Oxy)hydroxide Minerals under Early Earth Conditions

2021 ◽  
Author(s):  
Erika Flores ◽  
Eduardo Martinez ◽  
Laura E. Rodriguez ◽  
Jessica M. Weber ◽  
Arezoo Khodayari ◽  
...  
Keyword(s):  
Amino Acids ◽  
Phosphate Adsorption ◽  
Early Earth

scholarly journals Effect of co-ingestion of amino acids with rice on glycaemic and insulinaemic response

2015 ◽  
Vol 114 (11) ◽  
pp. 1845-1851 ◽  
Author(s):  
Yean Yean Soong ◽  
Joseph Lim ◽  
Lijuan Sun ◽  
Christiani Jeyakumar Henry
Keyword(s):  
Amino Acids ◽  
Blood Glucose ◽  
Amino Acid ◽  
Glycaemic Index ◽  
Amino Acid Mixture ◽  
Postprandial Blood Glucose ◽  
Acid Mixture ◽  
White Rice ◽  
Amino Acid Mixtures

AbstractConsumption of high glycaemic index (GI) and glycaemic response (GR) food such as white rice has been implicated in the development of type 2 diabetes. Previous studies have reported the ability of individual amino acids to reduce GR of carbohydrate-rich foods. Because of the bitter flavour of amino acids, they have rarely been used to reduce GR. We now report the use of a palatable, preformed amino acid mixture in the form of essence of chicken. In all, sixteen healthy male Chinese were served 68 or 136 ml amino acid mixture together with rice, or 15 or 30 min before consumption of white rice. Postprandial blood glucose and plasma insulin concentrations were measured at fasting and every 15 min after consumption of the meal until 60 min after the consumption of the white rice. Subsequent blood samples were taken at 30-min intervals until 210 min. The co-ingestion of 68 ml of amino acid mixture with white rice produced the best results in reducing the peak blood glucose and GR of white rice without increasing the insulinaemic response. It is postulated that amino acid mixtures prime β-cell insulin secretion and peripheral tissue uptake of glucose. The use of ready-to-drink amino acid mixtures may be a useful strategy for lowering the high-GI rice diets consumed in Asia.

scholarly journals Isolation, purification and structure of exochelin MS, the extracellular siderophore from Mycobacterium smegmatis

1995 ◽  
Vol 305 (1) ◽  
pp. 187-196 ◽  
Author(s):  
G J Sharman ◽  
D H Williams ◽  
D F Ewing ◽  
C Ratledge
Keyword(s):  
Amino Acids ◽  
Mycobacterium Smegmatis ◽  
Methyl Esters ◽  
Three Dimensional ◽  
Iron Chelation ◽  
Peptide Bond ◽  
Exchange Chromatography ◽  
Peptide Bonds ◽  
Hydrolysis Of ◽  
Gallium Complex

The extracellular siderophore from Mycobacterium smegmatis, exochelin MS, was isolated from iron-deficiently grown cultures and purified to > 98% by a combination of ion-exchange chromatography and h.p.l.c. The material is unextractable into organic solvents, is basic (pI = 9.3-9.5), has a lambda max at 420 nm and a probable Ks for Fe3+ of between 10(25) and 10(30). Its structure has been determined by examination of desferri- and ferri-exochelin and its gallium complex. The methods used were electrospray-m.s. and one- and two-dimensional (NOESY, DQF-COSY and TOCSY) 1H n.m.r. The constituent amino acids were examined by chiral g.l.c analysis of N-trifluoroacetyl isopropyl and N-pentafluoropropionyl methyl esters after hydrolysis, and reductive HI hydrolysis, of the siderophore. The exochelin is a formylated pentapeptide: N-(delta-N-formyl,delta N-hydroxy-R-ornithyl) -beta-alaninyl-delta N-hydroxy-R-ornithinyl-R-allo-threoninyl-delta N-hydroxy-S-ornithine. The linkages involving the three ornithine residues are via their delta N(OH) and alpha-CO groups leaving three free alpha-NH2 groups. Although there are two peptide bonds, these involve the three R (D)-amino acids. Thus the molecule has no conventional peptide bond, and this suggests that it will be resistant to peptidase hydrolysis. The co-ordination centre with Fe3+ is hexadenate in an octahedral structure involving the three hydroxamic acid groups. Molecular modelling shows it to have similar features to other ferric trihydroxamate siderophores whose three-dimensional structures have been established. The molecule is shown to have little flexibility around the iron chelation centre, although the terminal (Orn-3) residue, which is not involved in iron binding except at its delta N atom, has more motional freedom.

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