Synthesis Of Dipeptides Research Articles

Dipeptide synthesis by l-amino acid ligase from Ralstonia solanacearum

Despite its utility, dipeptides have not been widely used due to the absence of an efficient manufacturing method. Recently, a novel method for effective production of dipeptides using l-amino acid α-ligase (Lal) is presented. Lal, which is only identified in Bacillus subtilis, catalyzes dipeptide synthesis from unprotected amino acids in an ATP-dependent manner. However, not all the dipeptide can be synthesized by Lal from B. subtilis (BsLal) due to its substrate specificity. Here, we attempted to find a novel Lal exhibiting different substrate specificity from BsLal. By in silico screening based on the amino acid sequence of BsLal, RSp1486a an unknown protein from Ralstonia solanacearum was found to show the Lal activity. RSp1486a exhibited different substrate specificity from BsLal, and preferably synthesized hetero-dipeptides where more bulky amino acid was placed at N terminus and less bulky amino acid was placed at C terminus in opposition to those synthesized by BsLal.

ChemInform Abstract: Use of Di‐tert‐butyl‐dicarbonate Both as a Protecting and Activating Group in the Synthesis of Dipeptides.

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Synthesis of a Precursor Dipeptide of Thymopentin in Organic Solvents by an Enzymatic Method

The protease‐catalyzed, kinetically controlled synthesis of a precursor dipeptide of thymopentin(TP‐5), Z‐Arg‐Lys‐NH2 in organic solvents was studied. Z‐Arg‐OMe was used as the acyl donor and Lys‐NH2 was used as the nucleophile. An industrial alkaline protease alcalase and trypsin were used to catalyze the synthesis of the target dipeptide in water‐organic cosolvent systems. The conditions of the synthesis reaction were optimized by examining the effects of several factors, including organic solvents, water content, temperature, pH, and reaction time on the yield of Z‐Arg‐Lys‐NH2. The optimum conditions using alcalase as the catalyst are pH 10.0, 35°C, in acetonitrile/DMF/Na2CO3‐NaHCO3 buffer system (80∶10∶10, V/V), 6 h, with the dipeptide yield of 71.1%. Compared with alcalase, the optimum conditions for trypsin are pH 8.0, 35°C, in ethanol/Tris‐HCl buffer system (80∶20, V/V), 4 h, with the dipeptide yield of 76.1%.

Synthesis and antimalarial evaluation of cyclic beta-amino acid-containing dipeptides.

This paper describes an efficient synthesis and the antiparasitic evaluation of cyclic β-amino acid-containing dipeptides 3.1-3.6 and 4.1-4.5. The antimalarial properties of all these dipeptides have been evaluated in vitro against Plasmodium falciparum and in vivo against Plasmodium berghai. Compounds 4.4 and 4.5 have been found to be very effective in this respect, with IC50 values of 3.87 and 3.64 μg/mL in the in vitro test, while 4.5 has also been found to be active in the in vivo evaluation.

Biomimetic catalysis of diketopiperazine and dipeptide syntheses.

Entry for the Table of Contents Modular, supramolecular catalysts based on the coiled coil peptide scaffold and designed to mimic nonribosomal peptide synthetases are demonstrated to catalyze the formation of diketopiperazine and linear dipeptides for several aminoacyl substrates. We further demonstrate that the nature of the active site residues in the peptide catalysts can be used to effect directed intermodular aminoacyl transfer processes and govern the relative yields of diketopiperazine, linear dipeptide, and hydrolyzed substrate.

Biomimetic Catalysis of Diketopiperazine and Dipeptide Syntheses

Modulare supramolekulare Katalysatoren mit einem doppelthelical gewundenen Peptidgerüst, die als Mimetika nichtribosomaler Peptidsynthetasen entworfen wurden, katalysieren die Bildung von Diketopiperazinen und linearen Dipeptiden aus einer Reihe von Aminoacylsubstraten (siehe Schema). Je nach Art der Aminosäurereste im aktiven Zentrum des Peptidkatalysators lassen sich der gerichtete intermodulare Aminoacyltransfer und die relativen Ausbeuten an Diketopiperazin, linearem Dipeptid und hydrolysiertem Substrat steuern.

Dipeptide synthesis in biphasic medium: evaluating the use of commercial porcine pancreatic lipase preparations and the involvement of contaminant proteases

Dipeptide syntheses starting from Ac-L-Tyr-OEt or Z-L-X-OMe (X: Asp, Tyr, Phe, Arg, Lys or Thr) and glycine amide in biphasic reaction media were achieved using two commercially available porcine pancreatic lipase (PPL) preparations (crude (cPPL) and purified PPL (pPPL)). Under the mild conditions employed, α-chymotrypsin, a pancreatic protease that also presents esterase activity, catalyzed Ac-L-Tyr-Gly-NH2 synthesis with high productivity. Product hydrolysis also occurred in most of the syntheses studied. Polyacrylamide gel electrophoresis, enzymatic assays employing specific chromogenic substrates and size-exclusion chromatography revealed that cPPL and pPPL contain contaminant proteases and, therefore, exhibit esterase and amidase activities. Overall, these data indicate that those contaminants may be the main catalysts of peptide bond synthesis when Nα-blocked-L-amino acid esters and the commercial PPL preparations are used. On the other hand, such data do not contest the possibility of using such enzyme preparations as an inexpensive source of catalysts for dipeptide synthesis under soft conditions.

Use of Di‐tert‐butyl‐dicarbonate Both as a Protecting and Activating Group in the Synthesis of Dipeptides

Amide formation from amino acids was achieved in an easy and convenient one‐pot procedure using di‐tert‐butyl dicarbonate both as a protecting and an activating agent. A number of dipeptides have been synthesized in good yields.

A Robust and Convergent Synthesis of Dipeptide−DOTAM Conjugates as Chelators for Lanthanide Ions: New PARACEST MRI Agents

A generally applicable synthetic approach to dipeptide-DOTAM conjugates has been developed which is based on the peralkylation of 1,4,7,10-tetraazacyclododecane (cyclen) with protected N-iodoacetyl dipeptides. Standardized procedures were used for the alkylation, metalation, and purification of the resultant lanthanide complexes. Using this approach, we have been able to rapidly and reliably prepare and screen five different ligands each with up to six lanthanide ions. This preliminary investigation has identified several paramagnetic compounds with strong chemical exchange saturation transfer (PARACEST) properties in water at physiological temperature and pH. Extension of the synthetic approach to a wide variety of amino acids is possible.

Helical Pores Self-Assembled from Homochiral Dendritic Dipeptides Based on l-Tyr and Nonpolar α-Amino Acids

The synthesis of dendritic dipeptides (4-3,4-3,5)12G2-CH2-Boc-L-Tyr-X-OMe where X = Gly, L-Val, L-Leu, L-Ile, L-Phe, and L-Pro is reported. Their self-assembly in bulk and in solution and the structural and retrostructural analysis of their periodic assemblies were compared to those of the previously reported and currently reinvestigated dendritic dipeptides with X = L-Ala. All dendritic dipeptides containing as X nonpolar alpha-amino acids self-assemble into helical porous columns. The substituent of X programs the structure of the helical pore and the resulting periodic array, in spite of the fact that its molar mass represents only between 0.05 and 4.77% from the molar mass of the dendritic dipeptide. In addition to the various 2-D columnar lattices, the dendritic dipeptides based on L-Ala, L-Leu, and L-Phe self-organize into 3-D hexagonal columnar crystals while those based on L-Val and L-Ile into an unknown columnar crystal. The principles via which the aliphatic and aromatic substituents of X program the structure of the helical pores indicate synthetic pathways to helical pores with bioinspired functions based on artificial nonpolar alpha-amino acids.

Ribozyme-Catalyzed Dipeptide Synthesis in Monovalent Metal Ions Alone

Previously we have identified a highly active ribozyme (R180, cis ribozyme) that can catalyze dipeptide synthesis using N-biotinylcaproyl-aminoacyl-adenylate anhydride (Bio-aa-5'-AMP) as its substrate. In this work, we re-engineered the cis R180 ribozyme into a 158-nt trans ribozyme (TR158) and designed a new substrate (5'-Phe-linker-20-mer). First, the metal ion requirements were examined and compared between the two ribozymes. Both R180 and TR158 ribozymes were active in Mg2+ and Ca2+ but inert with Zn2+, Cu2+, Mn2+, and Co2+. It is intriguing that both ribozymes were highly active in Li+, Na+, or K+ alone but showed very low activity with NH4+. The two ribozymes showed similar linear concentration dependence on Li+ and K+, while they displayed different dependency behavior on Mg2+. Moreover, by using the trans system, the detailed kinetic studies and pH dependent experiments were performed in either 10 mM Mg2+ or 1.0 M Li+. Analysis of kcat and Km values obtained at different pHs (6.0 to 9.0) indicated that it is the catalytic activity of the ribozyme but not the substrate binding affinity that changes significantly with pH. The slopes of the linear parts of the pH-rate plots were close to 1.0 in both Mg2+- and Li+-mediated reactions, suggesting that one proton transfer is involved in the rate-limiting step of catalysis. Overall, our results suggest that Mg2+ and Li+ function similarly in the ribozyme-catalyzed dipeptide synthesis.

Purification and characterization of a novel imidazole dipeptide synthase from the muscle of the Japanese eel Anguilla japonica

We have purified a novel enzyme from eel white muscle which catalyzes the syntheses of imidazole dipeptides, such as carnosine (β-alanyl- l-histidine), anserine (β-alanyl-π-methyl- l-histidine), and balenine (ophidine; β-alanyl-τ-methyl- l-histidine), directly from their precursors. The enzyme was purified 1130-fold from eel muscle by a series of column chromatographies. Although eel muscle contains a large amount of carnosine and only trace amounts of anserine and balenine, the anserine synthesizing activity was by far the highest. From gel permeation chromatography, the molecular mass of the enzyme was calculated to be 275 kDa. SDS-PAGE of the purified enzyme represented a band around 43 kDa, suggesting that the native enzyme is a hexamer or heptamer. The optimal pH and temperature were around 9.5 and 60 °C, respectively. K m values for β-alanine and π-methyl- l-histidine were 44 and 89 mM, respectively. The enzyme was greatly activated by Zn 2+ and inhibited by EDTA. The N-terminal amino acid sequence of 25 residues of the purified enzyme showed 52% amino acid identity to 38–62 residues of zebrafish haptoglobin precursor. The purified enzyme also exhibited hydrolytic activity against these imidazole dipeptides.

Syntheses of dipeptides containing (1 R,5 S)-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2( S)-carboxylic acid ( 4), (1 R,5 S)-spiro[3-azabicyclo[3.1.0]hexane-6,1′-cyclopropane]- 2( S)-carboxylic acid ( 5) and (1 S,5 R)-6,6-dimethyl-3-azabicyclo[3.1.0]hexane-2( S)-carboxylic acid ( 6)

Versatile syntheses of dipeptides that incorporate the 3-azabicyclo[3.1.0]hexane system are described.

Novel Furanoid α-Substitued α-Amino Acid as a Potent Turn Mimic in Peptide Synthesis

A stereoselective approach has been developed to the new sugar amino acid and potential potent turn mimic 5-O-(tert-butyldimethylsilyl)-3-deoxy-1,2-O-isopropylidene-3-methoxycarbonylamino-alpha-D-xylofuranose 3-C-carboxylic acid (12), via the [3,3]-sigmatropic rearrangement of allylic thiocyanates (Z)-6 and (E)-7, prepared from D-xylose. The synthesis of a new dipeptide 13 is also described.

Dipeptide Synthesis by an Aminopeptidase from Streptomyces septatus TH-2 and Its Application to Synthesis of Biologically Active Peptides

Dipeptide synthesis by aminopeptidase from Streptomyces septatus TH-2 (SSAP) was demonstrated using free amino acid as an acyl donor and aminoacyl methyl ester as an acyl acceptor in 98% methanol (MeOH). SSAP retained its activity after more than 100 h in 98% MeOH, and in the case of phenylalanyl-phenylalanine methyl ester synthesis, the enzyme reaction reached equilibrium when more than 50% of the free phenylalanine was converted to the product. In an investigation of the specificity of SSAP toward acyl donors and acyl acceptors, SSAP showed a broad specificity toward various free amino acids and aminoacyl methyl esters. Furthermore, we applied SSAP to the synthesis of several biologically active peptides, such as aspartyl-phenylalanine, alanyl-tyrosine, and valyl-tyrosine methyl esters.

Synthesis of a precursor dipeptide of RGDS (Arg‐Gly‐Asp‐Ser) catalysed by the industrial protease alcalase

Synthesis of Bz-Arg-Gly-NH(2) (N-benzoylargininylglycinamide) [a precursor dipeptide of RGDS (Arg-Gly-Asp-Ser)] catalysed by protease in water/organic co-solvent systems was studied. Starting substrates were N-benzoyl-L-arginine ethyl ester hydrochloride (acyl donor) and glycinamide (nucleophile). Acetonitrile was selected as the organic solvent. Alcalase, an industrial alkaline protease, was applied to the synthesis of the target dipeptide. The conditions of the synthesis reaction were optimized by examining the effects of several factors, including water content, temperature, pH, molar ratio of the substrates and reaction time, on the yield of Bz-Arg-Gly-NH(2). The optimum conditions were established to be pH 10.0, 45 degrees C, in acetonitrile/0.1 M Na(2)CO(3)/NaHCO(3) buffer system (90:10, v/v) for 1 h with a dipeptide yield of 82.9%.

Self-Assembly, Structural, and Retrostructural Analysis of Dendritic Dipeptide Pores Undergoing Reversible Circular to Elliptical Shape Change

The synthesis of dendritic dipeptides (4-3,4-3,5-4)12G2-CH(2)-Boc-L-Tyr-L-Ala-OMe and (4-3, 4-3,5-4)12G2-CH(2)-Boc-D-Tyr-D-Ala-OMe is described. These dendritic dipeptides self-assemble into porous elliptical and circular columns that in turn self-organize into centered rectangular columnar and hexagonal columnar periodic arrays. The transition from porous elliptical to porous circular columns is mediated in a reversible or irreversible way by the thermal history of the sample. A method to determine the dimensions of hollow elliptical and circular columns by the reconstruction of the small-angle powder X-ray diffractograms of the centered rectangular or hexagonal columnar lattices was elaborated. This technique together with wide-angle X-ray experiments performed on aligned fibers provided access to the structural and retrostructural analysis of elliptical supramolecular pores. This procedure is general and can be adapted for the determination of the dimensions of pores of any columnar shape.

Alcalase‐Catalyzed, Kinetically Controlled Synthesis of a Precursor Dipeptide of RGDS in Organic Solvents

The protease‐catalyzed, kinetically controlled synthesis of a precursor dipeptide of RGDS, Z‐Asp‐Ser‐NH2 in organic solvents was studied. Alcalase, an industrial alkaline protease, was used to catalyze the synthesis of the target dipeptide in water‐organic cosolvents systems with Z‐Asp‐OMe as the acyl donor and Ser‐NH2 as the nucleophile. Acetonitrile was selected as the organic solvent from acetonitrile, ethanol, methanol, DMF, DMSO, ethyl acetate, 2‐methyl‐2‐propanol, and chloroform tested under the experimental conditions. The conditions of the synthesis reaction were optimized by examining the effects of several factors, including water content, temperature, pH, and reaction time on the Z‐Asp‐Ser‐NH2 yields. The optimum conditions are pH 10.0, 35°C, in acetonitrile/Na2CO3‐NaHCO3 buffer system (85:15, v/v), 6 h, with a dipeptide yield of 75.5%.

Synthesis of mono Nα-trifluoroethylated cyclic dipeptides

Trifluoroethylated N-termini in linear dipeptides l-TyrXOR [X = Gly, d-Ala, l-Leu, l-Phe, and l-Glu; R = H, Me, Et] exhibit sufficient nucleophilicity to give piperazine-2,5-dione ring formation through intramolecular cyclization reaction in acidic aqueous solutions. The reactions occur in high yield and with absolute configuration retention.

Programming the Internal Structure and Stability of Helical Pores Self-Assembled from Dendritic Dipeptides via the Protective Groups of the Peptide

The synthesis of dendritic dipeptides (4-3,4-3,5)12G2-CH2-X-L-Tyr-L-Ala-OMe with X = Boc, Moc, and Ac; their self-assembly in bulk and in solution; and the structural and retrostructural analysis of their supramolecular helical porous assemblies are reported. The dimensions, structure, internal order, thermal stability of the supramolecular helical pores, and conformations of the dendron and supramolecular dendrimer are programmed by the nature of the protective groups of the dipeptide. The ability of the protective groups to program the structure of the helical pore reveals the simplest design strategy that complements the more complex strategies based on the architecture of the dendron, the stereochemistry, and the structure of the dipeptide.