- Neutrophil-mediated oxidation of enkephalins via myeloperoxidase-dependent addition of superoxide
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Neutrophils play a major role in acute inflammation in part by generating superoxide and an array of other reactive species. These white blood cells also contribute to protection against inflammatory pain by releasing opioid peptides. The biochemical interactions of enkephalins with neutrophil-derived oxidants are not well understood. In this investigation we reveal that neutrophils use myeloperoxidase to oxidize enkephalins to their corresponding tyrosyl free radicals, which react preferentially with the superoxide to form a hydroperoxide. In methionine enkephalin, rapid intramolecular oxygen transfer from the hydroperoxide to the Met sulfur results in the formation of a sulfoxide derivative. This reaction may occur at sites of inflammation where enkephalins are released and neutrophils generate large amounts of superoxide. Hydroperoxide formation destroys the aromatic character of the Tyr residue by forming a bicyclic structure via conjugate addition of the terminal amine to the phenol ring. As the N-terminal Tyr and its amino group are essential for their opiate activity, we hypothesize that oxidative modification of this residue should affect the analgesic activity of enkephalins.
- Nagy, Péter,Kettle, Anthony J.,Winterbourn, Christine C.
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- IMPROVED DEPROTECTION IN SOLID PHASE PEPTIDE SYNTHEIS: QUANTITATIVE REDUCTION OF METHIONINE SULFOXIDE TO METHIONINE DURING HF CLEAVAGE
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The reduction of methionine sulfoxide residues in peptides was found to be quantitative by treatment with a low concentration of HF in dimethyl-sulfide (HF:dimethylsulfide, 1:3, v/v).The reduction was dependent on the acidity function of HF and was optimal with an HF concentration between 25percent and 40percent.The low HF concentration cleavage reagent also deprotected most of the benzyl alcohol-derived protecting groups.
- Tam, James P.,Heath, William F.,Merrifield, R. B.
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- Sustainable Peptide Synthesis Enabled by a Transient Protecting Group
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The growing interest in synthetic peptides has prompted the development of viable methods for their sustainable production. Currently, large amounts of toxic solvents are required for peptide assembly from protected building blocks, and switching to water as a reaction medium remains a major hurdle in peptide chemistry. We report an aqueous solid-phase peptide synthesis strategy that is based on a water-compatible 2,7-disulfo-9-fluorenylmethoxycarbonyl (Smoc) protecting group. This approach enables peptide assembly under aqueous conditions, real-time monitoring of building block coupling, and efficient postsynthetic purification. The procedure for the synthesis of all natural and several non-natural Smoc-protected amino acids is described, as well as the assembly of 22 peptide sequences and the fundamental issues of SPPS, including the protecting group strategy, coupling and cleavage efficiency, stability under aqueous conditions, and crucial side reactions.
- Avrutina, Olga,Knauer, Sascha,Koch, Niklas,Kolmar, Harald,Meusinger, Reinhard,Uth, Christina
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supporting information
p. 12984 - 12990
(2020/06/01)
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- Synthesis of Met-enkephalin by solution-phase peptide synthesis methodology utilizing para-toluene sulfonic acid as N-terminal masking of l-methionine amino acid
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The Met-enkephalin, Tyr-Gly-Gly-Phe-Met, was synthesized by the solution-phase synthesis (SPS) methodology employing -OBzl group as carboxyls' protection, while the t-Boc groups were employed for the N-terminal α-amines' protection for the majority of the amino acids of the pentapeptide sequence. The l-methionine (l-Met) amino acid was used as PTSA.Met-OBzl obtained from the simultaneous protection of the α-amino, and carboxyl group with para-toluene sulfonic acid (PTSA) and as-OBzl ester, respectively in a C-terminal start of the 2?+?2?+?1 fragments condensation convergent synthetic approach. The protection strategy provided a short, single-step, simultaneous, orthogonal, nearly quantitative, robust, and stable process to carry through the protected l-methionine and l-phenylalanine coupling without any structural deformities during coupling and workups. The structurally confirmed final pentapeptide product was feasibly obtained in good yields through the current approach.
- Khan, Riaz A.
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p. 884 - 888
(2016/11/11)
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- Nicotinoyl peptide derivatives and cosmetic composition comprising the same
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The present invention relates to nicotinoyl peptide derivatives, wherein neuropeptides are connected to nicotinic acid, and a cosmetic composition comprising the same. The peptide derivatives according to the present invention have good collagen generation and anti-inflammatory activities to show an excellent anti-wrinkle effect, little cytotoxicity, water-solubility, and good stability during long-term storage. Therefore, they can be effectively used for preparing an anti-aging cosmetic composition.
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- Simple, economical and flexible apparatus for solid phase peptide synthesis
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Solid phase peptide synthesis basically involves repetitive deblocking and coupling reactions. In order to make these repetitive operations fast and convenient, the deblocking and coupling reactions are carried out in specially designed apparatus, which are called solid phase peptide synthesis apparatus. These apparatus are expensive, hence unaffordable for many laboratories. In addition, these apparatus lack the operational flexibility for varying reaction parameters such as reaction time, temperature, pressure, sonication, microwave irradiation, etc. In order to make peptide synthesis convenient and flexible with respect to reaction conditions and affordable for many laboratories, a two-vessel approach has been proposed. In this approach, coupling reaction is carried out in a round bottom flask with overhead stirrer, and the filtration (work-up) is carried out in a specially designed filtration-vessel. Using the two-vessel approach, D-Met-enkephalins (pentapeptides, Tyr-Gly-Gly-Phe-D-Met) and some of its derivatives involving lengthy reactions have been synthesized on Merrifield resin. This approach is very convenient for studying variations in reaction conditions and is good for synthesizing short peptides (10 amino acids). By this approach 1-100 g resin can be handled in a laboratory without any additional cost. This approach can be extrapolated to solid phase syntheses as well.
- Satyanarayana, Kota,Rajesh Kumar,Venkanna
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p. 1143 - 1147
(2008/09/18)
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- Convenient high yielding gram scale solution synthesis of methionine-enkephalin
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A simple, large-scale synthesis of a cytokine, methionine-enkephalin, Tyr-Gly-Gly-Phe-Met, has been elaborated. Classical solution peptide chemistry methods without protection of amino acid side-chain functions and l+(2+2) segment condensation were used. A nine-step synthesis from commercial amino acid derivatives was developed with yields ranging from 86% to 99%, averaging 92%. The purity of all intermediates was found to be 99.0-100% by HPLC. The process has been used to prepare greater than 150 g quantities of the pentapeptide as a monohydrate of 100% purity. Hydantoin formation was observed during saponification of Boc-TyrGly-Gly-Phe-Met-OMe and minimised.
- Masiukif.wicx, Elzbieta,Rzeszotarska, Barbara
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p. 1672 - 1675
(2007/10/03)
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- Reduction of methionine sulfoxide with NH4I/TFA: Compatibility with peptides containing cysteine and aromatic amino acids
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The reduction of methionine sulfoxide with ammonium iodide in trifluoroacetic acid has been studied in peptides containing cysteine, histidine, tyrosine or tryptophan residues. While histidine and tyrosine have proved to be stable under the experimental conditions, cysteine is oxidized to cystine and tryptophan dimerizes to form 2-indolylindolenine derivatives. The use of methyl sulfide to increase the reduction rate minimizes the problem and protection of indole ring with the formyl group avoids the side reaction for this amino acid.
- Vilaseca, Marta,Nicolas, Ernesto,Capdevila, Fina,Giralt, Ernest
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p. 15273 - 15286
(2007/10/03)
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- Effects of three peptidase inhibitors, amastatin, captopril and phosphoramidon, on the hydrolysis of [Met5]-enkephalin-Arg6-Phe7 and other opioid peptides
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The contents of [Met5]-enkephalin-Arg6-Phe7 (met-enk-RF) and its six hydrolysis products: Y, YG, YGG, YGGF, YGGFM, and YGGFMR were estimated after incubating met-enk-RF with either a guinea-pig ileal or striatal membrane fraction for various times at 37°C. After 45 min incubation with either ileal or striatal membranes, met-enk-RF was completely hydrolyzed, yielding Y as the major product. Incubation with either membrane preparation for 60 min in the presence of the aminopeptidase inhibitor amastatin hydrolyzed 90 or 92% of met-enk-RF, respectively, with YGG being the major product. If the dipeptidyl carboxypeptidase I inhibitor captopril is also included in the incubation, met-enk-RF hydrolysis decreases by about half for both membranes, with YGG remaining the major product. Inclusion of three peptidase inhibitors, amastatin, captopril, and phosphoramidon (inhibition of endopeptidase-24.11) further reduced met-enkhydrolysis, with 87% or more remaining intact. This shows that met-enk-RF was mainly hydrolyzed by three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive dipeptidyl carboxypeptidase I and phosphoramidon-sensitive endopeptidase-24.11, in both ileal and striatal membranes. Additionally, estimations of [Leu5]-enkephalin (leu-enk), α- and β-neoendorphins (α- and β-neoends), and dynorphin B (dyn B) contents after incubating the individual peptides with striatal membrane for 60 min in the presence of the three peptidase inhibitors showed that 98, 32, 5, and 23%, respectively, remained intact. Our previous studies together with the data obtained here show that one group of endogenous opioid peptides: met-enk, leu-enk, met-enk-RF, met-enk-RGL, and dyn A-(1-8) are largely or almost exclusively hydrolyzed by the three enzymes, amastatin-sensitive aminopeptidase, captopril-sensitive dipeptidyl carboxypeptidase I, and phosphoramidon-sensitive endopeptidase-24.11, and indicate that an unidentified fourth enzyme(s) is involved in the hydrolysis of another group of peptides: α-neoend, β-neoend, and dyn B.
- Hiranuma, Toyokazu,Kitamura, Ken,Taniguchi, Takao,Kobayashi, Tomomi,Tamaki, Raita,Kanai, Masayuki,Akahori, Kazuhito,Iwao, Kayoko,Oka, Tetsuo
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p. 276 - 282
(2007/10/03)
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- Differences in the hydrolysis of enkephalin congeners by the two domains of angiotensin converting enzyme
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The hydrolysis of enkephalin (Enk) congeners by the isolated N- (N-ACE) and C-domain of angiotensin I converting enzyme (ACE) and by the two-domain somatic ACE was investigated. Both Leu5- and Met5-Enk were cleaved faster by the C-domain than by N-ACE; rates with somatic ACE were 1600 and 2500 nmol/min/nmol enzyme with both active sites being involved. Substitution of Gly2 by D-Ala2 reduced the rate to 1/3rd to 1/7th of that of the Enks. N- ACE cleaved Met5-Enk-Arg6-Phe7 faster than the C-domain, probably with the highest turnover number of any naturally occurring ACE substrate (7600 min- 1). This heptapeptide is also hydrolyzed in the absence of Cl-, but the activation by Cl- is unique; Cl- enhances the hydrolysis of the heptapeptide by N-ACE but inhibits it by the C-domain, yielding about a 5- fold difference in the turnover number at physiological pH. This difference may result in the predominant role of the N-domain in converting Met5-Enk- Arg6-Phe7 to Enk in vivo.
- Deddish, Peter A.,Jackman, Herbert L.,Skidgel, Randal A.,Erdoes, Ervin G.
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p. 1459 - 1463
(2007/10/03)
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- Phosphorylation of enkephalins enhances their proteolytic stability
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Pharmacological action of enkephalins as opioid peptides is limited because of their rapid degradation by endoproteases. A novel approach is used in this study to prolong the life of those peptides. Phosphorylation of N-terminal tyrosine residue is found to have a profound influence in improving the stability of [Met]enkephalin and [Leu]enkephalin against the action of aminopeptidase M. Whereas, breakdown of [Met]enkephalin and [Leu]enkephalin is essentially complete in less than one min when incubated at 37°C with purified aminopeptidase M (EC 3.4.11.2; substrate:enzyme = 1:0.1) in Tris buffer (pH 7.02), the corresponding phospho analogs are still detected 60 min after start of incubation. The rate of disappearance of phospho-[Met]enkephalin and phospho-[Leu]enkephalin follows first-order kinetics with half-lives of 7.3 and 8.8 min, respectively.
- Dass, Chhabil,Mahalakshmi
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p. 1039 - 1045
(2007/10/03)
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- Phosphorus-based Reagents in Peptide Synthesis: Synthesis of Methionine-Enkephalin and the Solution Conformation of its N-Diphenylphosphinoyl Derivative
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Met5enkephalin 1 was synthesized by solution phase synthesis using the diphenylphosphinoyl (Dpp) group for α-amino group protection and diphenylphosphinoyl-carboxylic acid mixed anhydrides for carboxylate activation.These reagents proved to be compatible with both tyrosine and methionine side chain functionalities.A (1)H NMR study of the solution conformation of the N-terminal-protected pentapeptide DppMe5enkephalin 2 in dimethyl sulfoxide suggests that the peptide backbone of this derivative adopts a major conformation possessing a type I' β-bend between residues Gly2-Gyl3 with the side chains of the Tyr1 and Phe4 lying on the same side of the plane of the bend.The predominant conformation of the Phe4 and Met5 side chains appear to be tg+.
- Smith, D. David,Boyd, Kenneth G.,Hopton, David,Baxter, Robert L.,Ramage, Robert
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p. 551 - 556
(2007/10/02)
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- Method and apparatus for the continuous polymer synthesis on a solid carrier
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The invention relates to a novel method and apparatus for the solid-phase synthesis of polymers such as polypeptides wherein an elongated, preferably band-like carrier (1) is used. The attachment of the reactants is realized by suc-cessive introduction of the carrier (1) into the appropri-ate baths. This method allows continuous preparation of polypeptides, polynucleotides, etc., The apparatus comprises a solid, insoluble, elongated car-rier (1) comprising functional groups and an arrangement of successive reaction zones (5, 7) and processing zones (4, 6, 8) of a sequence identical with that of the reac-tion and processing steps of the process sequence of the respective synthesis, and comprises means (2a, 2b) for successively contacting the carrier (1) with the reaction and processing liquids.
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- Sulphur Trioxide/Thiol: A Novel System for the Reduction of Methionine Sulphoxide
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A new method for the effective reduction of methionine sulphoxide in protected peptides with sulphur trioxide and thiol has been developed.In practice, a combination of dimethylformamide-sulphur trioxide complex and ethane-1,2-dithiol was found effective, the presence of pyridine in the reaction medium being found necessary for the reduction to proceed.Methionine sulphoxide in two types of protected methionine-enkephalins was efficiently reduced to methionine by this reduction system at 20 deg C in an hour.The (p-methylsulphinyl)benzyl protecting group was also reduced to (p-methylthio)benzyl simultaneously with the reduction of methionine sulphoxide.Subsequent deprotection afforded methionine-enkephalin of high purity in each case.
- Futaki, Shiroh,Yagami, Takeshi,Taike, Takashi,Akita, Tadashi,Kitagawa, Kouki
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p. 653 - 658
(2007/10/02)
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- SYNTHESIS OF ENKEPHALINS BY THE METHOD OF POLYMERIC ACTIVATED ESTERS BASED ON 4-HYDROXY-3-NITROBENZOPHENONE
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Leucine- and methionine-enkephalins have been synthesized by the successive growth of the peptide chain from the C-end by the method of polymeric activated esters based on 4-hydroxy-3-nitrobenzophenone with yields of 90 and 70percent, respectively, calculated on the initial C-terminal amino acid.Polystyrene with 2percent of divinylbenzene was used as the polymeric matrix.Using the synthesis of methionine-enkephalin as an example, the possibility has been shown of using polymeric activated esters for the synthesis of peptides with a free carboxy group.
- Grigor'ev, E. I.,Chernova, S. V.
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p. 468 - 474
(2007/10/02)
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- Polypeptide and its production and use
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Novel polypeptide of the formula: H-Tyr-Gly-Gly-Phe-Met-Lys-Pro-Tyr-Thr-Lys-Gln-Ser-His-Lys-Pro-Leu-Ile-Thr-Leu-Leu-Lys-His-Ile-Thr-Leu-Lys-Asn-Glu-Gln-OH is useful as an analgesic agent. Methods of its preparation are also disclosed.
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- A Convenient Synthesis of Met-enkephalin Using 1-β-Naphthalenesulphonyloxybenzotriazole for Peptide Bond Formation
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A convenient procedure for the synthesis of Met-enkephalin involving the use of 1-β-naphthalenesulphonyloxybenzotriazole as the peptide coupling reagent is described.Boc group is employed for the protection of α-NH2 functions of amino acids and its cleavage from the intermediate peptides is brought about by HCOOH in the presence of C6H5-OCH3 and SH-(CH2)2-SH without the formation of side products.The resulting formates are converted to the corresponding hydrochlorides prior to their coupling with the carboxy component.All the intermediate peptides have been obtained in high yields.
- Sharma, S. D.,Mathur, K. B.
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p. 227 - 229
(2007/10/02)
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- O-(N-ACYLAMINOACYL)-2-PYRIDYLMETHYLKETOXIMES AND THEIR USE IN PEPTIDE SYNTHESIS
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Preparation of Leu-enkephalin, Met-enkephalin and one analog of Leu-enkephalin by using O-(N-acylaminoacyl)-2-pyridylketoximes is described.Both the side products and the unreacted active amino acid derivatives were removed by utilizing the formation of a copper complex with 2-pyridylmethylketoxime.
- Plucinski, Tomasz,Kupryszewski, Gotfryd
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p. 573 - 582
(2007/10/02)
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- Efficient Removal of N-Benzyloxycarbonyl Group by a 'Push-Pull' Mechanism using Thioanisole-Trifluoroacetic Acid, Examplified by a Synthesis of Met-Enkephalin
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The N-benzyloxycarbonyl group can be smoothly cleaved under mild conditions, using thioanisole-trifluoroacetic acid, which can deprotect O-benzyltyrosine without the formation of O-to-C rearrangement products; this deblocking method was successfully applied to the synthesis of Met-enkephalin.
- Kiso, Yoshiaki,Ukawa, Kazuko,Akita, Tadashi
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p. 101 - 102
(2007/10/02)
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- A deblocking method using thioether-sulfonic acid systems. Application to the synthesis of met-enkephalin
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Thioanisole-trifluoromethanesulfonic acid and thioanisole-methanesulfonic acid systems were found to be useful as deblocking methods in the synthesis of a methionine-containing peptide, Met-enkephalin, without any side reaction.
- Kiso,Ito,Nakamura,et al.
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p. 1472 - 1475
(2007/10/06)
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