556-33-2Relevant articles and documents
On the Possible Role of Montmorillonites in Prebiotic Peptide Formation
Bujdak, J.,Slosiarikova, H.,Texler, N.,Schwendinger, M.,Rode, B. M.
, p. 1033 - 1040 (1994)
The ability of montmorillonite clay minerals for catalyzing peptide formation from amino acids in aqueous solution has been investigated using glycine and Cu(2+) and Ca(2+) containing montmorillonites as reaction systems.Evaporation cycle experiments showed that minor amounts of di- and tripeptide are formed from the amino acid.Further polymerization of dipeptide, however, seems to be more favoured by this reaction system than the initial step of dipeptide formation, and a possible role of clays in prebiotic peptide evolution could be seen therefore in the prolongation of peptide chains.Cu(2+) ions in the clay matrix did not show any advantage over the usual Ca(2+) ions embedded in natural montmorillonite. - Keywords: Prebiotic peptide formation; Evolution; Clay catalysis.
Influence of Alkali- and Alkaline-earth-metal Cations on the 'Salt-induced Peptide Formation' Reaction
Eder, Artur H.,Rode, Bernd M.
, p. 1125 - 1130 (1994)
The reaction mechanism of the salt-induced peptide formation from amino acids has been investigated by variation of the inorganic salt delivering Cl(1-) ions and providing the dehydrating effect.Chloride anions proved to be essential to prevent chelate complexation of the second amino acid.Upon exchange of sodium by other alkali- or alkaline-earth elements, peptide formation is still observed.The dipeptide yields are mainly determined by two factors: on the one hand the pH of the solution should be below 3 to prevent Cu(II)-catalysed peptide hydrolysis and give an optimum species distribution for peptide formation and above 2 to keep proton-catalysed peptide hydrolysis as low as possible; on the other hand by the concentration of the inorganic salt for removing water from the reaction and thus shifting the equilibrium towards the peptide side.The hydration enthalpies of the cations are the determining factor for the initial rate of peptide formation and lead to the series Mg(2+) > Ca(2+) > Ba(2+) > Na(1+) > NH4(1+) > K(1+) > Cs(1+).In the long run the initial advantage of divalent cations is overruled by stronger hydrolysis due to the lower pH of their solutions.The ion NH4(1+) is atypical, apparently due to its buffering ability.
Influence de composes a heterocycle azote et particulierement d'azoles non condenses sur des reactions "prebiotiques" de condensation d'acides α-amines induites par les polyphosphates an milieu aqueux
Rabinowitz, Joseph,Hampai, Aioub
, p. 962 - 966 (1980)
In previous experiments aqueous solutions of α-aminoacids in the presence of cyclic or linear polyphosphates, pH range 7-11, yielded up to 40percent of dipeptide but only 0.3-0.5percent of tripeptide .By addition of imidazole the yield of tripeptide could be increased about ten times .Therefore, we have studied for the condensation reaction of glycine the influence of the addition to aqueous solutions 0.1M in glycine and 0.1M in trimethaphosphate at room temperature, pH range 6.7-8.9, of several azoles (pyrrole, pyrazole, imidazole, 1,2,4-triazole and tetrazole), of adenine, guanine, uracil, cytosine, and of several nucleosides (adenosine, guanoside, uridine and cytydine).Among the produts studied, only 1,2,4-triazole and imidazole improve appreciably, by a factor of about 15, the yield of triglycine (up to 7.8percent).While it is very likely that imidazole has played an important role during prebiotic chemical evolution, it is not clear at present whether 1,2,4-triazole has a prebiotic significance.
PEPTIDE FORMATION FROM AMINO ACID WITH PARTICULATE SEMICONDUCTOR PHOTOCATALYSTS
Onoe, Jun,Kawai, Tomoji,Kawai, Shichio
, p. 1667 - 1670 (1985)
Peptides of diglycine to pentaglycine are formed from glycine under irradiation in the presence of particulate semiconductor photocatalysts such as TiO2, CdS, CdSe, MoS2, In2O3, and GaP, with and without Pt deposition.Platinization of the semiconductors efficiently enhanced the yield of the peptides.
Mechanochemical Prebiotic Peptide Bond Formation**
Cindro, Nikola,Grube?i?, Sa?a,Hernández, José G.,Me?trovi?, Ernest,Stolar, Tomislav,U?arevi?, Krunoslav
supporting information, p. 12727 - 12731 (2021/05/07)
The presence of amino acids on the prebiotic Earth, either stemming from endogenous chemical routes or delivered by meteorites, is consensually accepted. Prebiotically plausible pathways to peptides from inactivated amino acids are still unclear as most oligomerization approaches rely on thermodynamically disfavored reactions in solution. Now, a combination of prebiotically plausible minerals and mechanochemical activation enables the oligomerization of glycine at ambient temperature in the absence of water. Raising the reaction temperature increases the degree of oligomerization concomitantly with the formation of a commonly unwanted cyclic glycine dimer (DKP). However, DKP is a productive intermediate in the mechanochemical oligomerization of glycine. The findings of this research show that mechanochemical peptide bond formation is a dynamic process that provides alternative routes towards oligopeptides and establishes new synthetic approaches for prebiotic chemistry.
Optimized protocols for assessing libraries of poorly soluble sortase A inhibitors for antibacterial activity against medically-relevant bacteria, toxicity and enzyme inhibition
Alharthi, Sitah,Ziora, Zyta Maria,Moyle, Peter Michael
supporting information, (2021/11/30)
Increasing antimicrobial resistance is a major global health concern. Conventional antibiotics apply selection pressures, which promote the accumulation of resistant microbes. Anti-virulence strategies, in contrast, are less potent antimicrobials, but are less likely to select for resistance, can be combined with existing antibiotics to improve their activity, and in some cases can overcome antimicrobial resistance towards other antimicrobials. Sortase A inhibitors (SrtAIs) represent an exciting example of this class; however, many reported examples demonstrate poor water solubility, which complicates their biological assessment and activity. This includes reports that use antimicrobial concentrations of organic solvents or conditions that fail to solubilise these compounds for minimal inhibitory concentration (MIC) assessments. Herein, we report the first study to optimise screening processes for a library of prospective SrtAIs (trans-chalcone (TC), berberine (BR), curcumin (CUR), and quercetin (QC)), including comparative assessment of the effects of various co-solvent concentrations, along with comparative assessment of their antimicrobial activities against multiple disease relevant bacterial strains (methicillin-sensitive and resistant S. aureus, E. coli, and P. aeruginosa), inhibition of the sortase A enzyme, and toxicity towards mammalian cells (HEK-293), using these optimised conditions. Optimal solubility with minimal effect on bacterial viability was observed in the presence of 5% (v/v) dimethyl sulfoxide (DMSO)-Mueller-Hinton Broth. Three antimicrobial susceptibility tests (broth microdilution, agar dilution, and disk diffusion) were assessed for their ability to accurately determine minimal inhibitory concentration (MIC) data for each SrtAI. Broth microdilution and agar dilution were both effective; however, the broth microdilution assay required the addition of a colorimetric metabolic indicator (resazurin) to enable simple and reliable MIC determination due to the development of precipitants over time. In contrast, disk diffusion did not provide reliable zone of inhibition data. Identical MIC data was observed with methicillin-sensitive and -resistant S. aureus (MRSA; ATCC43300), with lower potency activity against E. coli and P. aeruginosa. Under these conditions, TC and CUR demonstrated significant toxicity towards human embryonic kidney (HEK-293) cells, with QC showing less toxicity and BR limited-to-no toxicity at its MIC. Overall, the findings of this work provide optimised processes, which will prove useful for the study of other poorly soluble antimicrobial agents and SrtAIs. The obtained data suggests that BR should be considered in preference to the other SrtAIs for the development of new antimicrobial formulations, based on its superior antimicrobial and SrtA inhibition potency, and greatly reduced toxicity.
BENZYL COMPOUND
-
Paragraph 0218-0219, (2019/02/05)
The purpose of the present invention is to provide a protecting group which improves the solubility of a compound having a functional group protected with the protecting group in an organic solvent and which is easily separated and purified after a reaction with avoiding solidification or insolubilization. Provided is a benzyl compound represented by Formula (1) where X1 represents —CH2OR14 (where R14 represents a hydrogen atom, a halogenocarbonyl group, or an active ester-type protecting group), —CH2NHR15 (where R15 represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or an aralkyl group), a halogenomethyl group, a methyl azide group, a formyl group, or an oxime; and at least one of R1, R2, R3, R4, and R5 is a group represented by Formula (2), and the remainders each represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, where R6 represents a linear or branched alkylene group having 1 to 16 carbon atoms; X2 represents O or CONR16 (where R16 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms); and A represents a group represented by Formula (3), (4), (5), (6), (7), (8), (9), (10), (11), (12), or (13).
Coupling-Reagent-Free Synthesis of Dipeptides and Tripeptides Using Amino Acid Ionic Liquids
Furukawa, Shinya,Fukuyama, Takahide,Matsui, Akihiro,Kuratsu, Mai,Nakaya, Ryotaro,Ineyama, Takashi,Ueda, Hiroshi,Ryu, Ilhyong
supporting information, p. 11980 - 11983 (2015/08/18)
A general method for the synthesis of dipeptides has been developed, which does not require any coupling reagents. This method is based on the reaction of readily available HCl salts of amino acid methyl esters with tetrabutylphosphonium amino acid ionic liquids. The isolation procedure of stepwise treatment with AcOH is easy to carry out. The method was extended to the synthesis of tripeptide, tyrosyl-glycyl-glycine, present in IMREG-1, also.
Molecular cloning and characterization of γ-Glutamyltranspeptidase from pseudomonas nitroreducens IFO12694
Imaoka, Masashi,Yano, Shigekazu,Okumura, Masashi,Hibi, Takao,Wakayama, Mamoru
experimental part, p. 1936 - 1939 (2011/06/11)
y-Glutamyltranspeptidase from Pseudomonas nitroreducens IFO12694 (PnGGT) exhibited higher hydro-lytic activity than transfer activity, as compared with other y-glutamyltranspeptidases (GGTs). PnGGT showed little activity towards most of L-amino acids and towards glycyl-glycine, which is often used as a standard y-glutamyl accepter in GGT transfer reactions. The preferred substrates for PnGGT as a y-glutamyl accepter were amines such as methylamine, ethylamine, and isopropylamine.
Structure and dynamics of the homologous series of alanine peptides: A joint molecular dynamics/NMR study
Graf, Juergen,Nguyen, Phuong H.,Stock, Gerhard,Schwalbe, Harald
, p. 1179 - 1189 (2008/04/18)
The φ,ψ backbone angle distribution of small homopolymeric model peptides is investigated by a joint molecular dynamics (MD) simulation and heteronuclear NMR study. Combining the accuracy of the measured scalar coupling constants and the atomistic detail of the all-atom MD simulations with explicit solvent, the thermal populations of the peptide conformational states are determined with an uncertainty of R helical conformations. No significant change in the distribution of conformers is observed with increasing chain length (Ala3 to Ala7). Trivaline samples all three major conformations significantly. Tryglycine samples the four corner regions of the Ramachandran space and exists in a slow conformational equilibrium between the cis and trans conformation of peptide bonds. The backbone angle distribution was also studied for the segment Ala3 surrounded by either three or eight amino acids on both N- and C-termini from a sequence derived from the protein hen egg white lysozyme. While the conformational distribution of the central three alanine residues in the 9mer is similar to that for the small peptides Ala3-Ala7, major differences are found for the 19mer, which significantly (30-40%) samples αR helical stuctures.
