1218-34-4Relevant articles and documents
A fundamental study of amadori rearrangement products in reducing sugar-amino acid model system by electrospray ionization mass spectrometry and computation
Zhang,Ruan,Wang,Ruan,Shao,Aalhus,Juárez
, p. 2941 - 2944 (2014)
It is crucial to characterize Amadori rearrangement products (ARPs) formed in the early stage of Maillard reaction, one of the most important modifications in food science. We setup a reaction model system using six selected amino acids (arginine, asparagines, glutamine, histamine, lysine and tryptophan) and their N-terminal acetylated forms with different reducing sugars for a fundamental study of Amadori rearrangement products. The effects on forming Amadori rearrangement products were studied by using electrospray ionization mass spectrometry (ESI-MS). The reaction rate was affected by reaction temperature, reaction time, property of sugars and amino acids and the fragmentation mechanism of Amadori rearrangement products was illustrated by tandem MS (MS2) with collision-induced dissociation. The proposed fragmentation mechanism of Amadori rearrangement products in MS2 was provided based on MS2 data and it was supported by their computational data of density functional theory (DFT) at the B3LYP/6-31++G(d,p) level.
Reaction of vitamin e compounds with n-nitrosated tryptophan derivatives and its analytical use
Mueller, Karsten,Korth, Hans-Gert,De Groot, Herbert,Kirsch, Michael
, p. 7532 - 7542 (2007)
We recently showed that nitrosated tryptophan residues may act as endogenous nitric oxide storage compounds. Here, a novel reaction of nitrosotryptophan derivatives is described, in the form of the release of nitric oxide from N-nitrosotryptophan derivatives initiated either by a-tocopherol or by its water-soluble form trolox. α-Tocopherol and trolox were found to release stoichiometric amounts of nitric oxide from N-acetylN-nitrosotryptophan as well as from the nitrosotryptophan residue in albumin. The reaction proceeds both in water and in lipophilic solution and reconstitutes the indole moiety of the tryptophan molecule quantitatively. During this reaction, α-tocopherol- and trolox-derived phenoxyl-type radicals were identified as intermediates by ESR spectrometry. The chemical mechanism of the NO-releasing process was established. Since S-nitrosothiols donot react under the applied conditions, it is suggested that the trolox-dependent release of nitric oxide may be utilizable for the detection of N-nitrosotryptophan residues in biological samples. Furthermore, as N-nitrosotryptophan derivatives do not undergo spontaneous decay in lipophilic environments, vitamin E may have the so far unrecognized function of preventing the accumulation of N-nitrosotryptophan residues to toxic concentrations in biological systems.
Comparison of HNO reactivity with tryptophan and cysteine in small peptides
Keceli, Gizem,Moore, Cathy D.,Toscano, John P.
, p. 3710 - 3713 (2014)
Recent discoveries of important pharmacological properties have drawn attention to the reactivity of HNO (azanone, nitroxyl) with biologically relevant substrates. Apart from its role in thiol oxidation, HNO has been reported to have nitrosative properties, for example, with tryptophan resulting in N-nitrosotryptophan formation. We have investigated the reactivity of HNO with tryptophan and small peptides containing either tryptophan or both a tryptophan and a cysteine residue. Our results point to the more reactive nature of cysteine towards HNO compared with tryptophan.
The biosynthetic pathway of crucifer phytoalexins and phytoanticipins: De novo incorporation of deuterated tryptophans and quasi-natural compounds
Pedras, M. Soledade C.,Okinyo-Owiti, Denis P.,Thoms, Ken,Adio, Adewale M.
, p. 1129 - 1138 (2009)
Although several biosynthetic intermediates in pathways to cruciferous phytoalexins and phytoanticipins are common, questions regarding the introduction of substituents at N-1 of the indole moiety remain unanswered. Toward this end, we investigated the potential incorporations of several perdeuterated d- and l-1′-methoxytryptophans, d- and l-tryptophans and other indol-3-yl derivatives into pertinent phytoalexins and phytoanticipins (indolyl glucosinolates) produced in rutabaga (Brassica napus L. ssp. rapifera) roots. In addition, we probed the potential transformations of quasi-natural compounds, these being analogues of biosynthetic intermediates that might lead to "quasi-natural" products (products similar to natural products but not produced under natural conditions). No detectable incorporations of deuterium labeled 1′-methoxytryptophans into phytoalexins or glucobrassicin were detected. l-tryptophan was incorporated in a higher percentage than d-tryptophan into both phytoalexins and phytoanticipins. However, in the case of the phytoalexin rapalexin A, both d- and l-tryptophan were incorporated to the same extent. Furthermore, the transformations of both 1′-methylindolyl-3′-acetaldoxime and 1′-methylindolyl-3′-acetothiohydroxamic acid (quasi-natural products) into 1′-methylglucobrassicin but not into phytoalexins suggested that post-aldoxime enzymes in the biosynthetic pathway of indolyl glucosinolates are not substrate-specific. Hence, it would appear that the 1-methoxy substituent of the indole moiety is introduced downstream from tryptophan and that the post-aldoxime enzymes of the glucosinolate pathway are different from the enzymes of the phytoalexin pathway. A higher substrate specificity of some enzymes of the phytoalexin pathway might explain the relatively lower structural diversity among phytoalexins than among glucosinolates.
Kinetics and Mechanism of the Nitrosation of N-Acetyltryptophan and of the Denitrosation of N-Acetyl-N1-nitrosotryptophan
Castro, Albino,Iglesias, Emilia,Leis, J. Ramon,Pena, M. Elena,Tato, Jose Vazquez,Williams, D. Lyn H.
, p. 1165 - 1168 (1986)
Both the formation and the denitrosation of N-acetyl-N1-nitrosotryptophan have been studied kinetically in aqueous solution at 25 deg C at acidities between 1M-HClO4 and pH 4.A value of 850 l mol-1 has been obtained for the equilibrium constant for the formation of N-acetyl-N1-nitrosotryptophan.At acidities (+>) greater than 0.1M the rate constants for both nitrosation and denitrosation increase linearly with the concentration of acid, and the reaction rates are unaffected by the addition of nucleophiles (Br- and SCN-).The results are consistent with a mechanism for nitrosation where the rate-limiting step is the proton transfer from the protonated N-nitroso species to the medium.For denitrosation the corresponding protonation of the nitrosamine is rate-limiting.These conclusions are confirmed by the results obtained when the reactions are carried out in heavy water.However, in the pH range 1-4 the rates of both nitrosation and denitrosation are independent of the acidity of the medium and are again unaffected by the presence of nucleophiles or buffers.It is suggested that in this region nitrosation occurs at C-3.This is followed by deprotonation and an internal NO migration from C to N which is rate-limiting.This mechanism also accounts for earlier results on the denitrosation reaction at even lower acidities (pH 4-7), where acid catalysis and nucleophilic catalysis are found.Results of experiments in heavy water are compatible with this mechanism.
Hydrogen/deuterium exchange of cross-linkable α-amino acid derivatives in deuterated triflic acid
Wang, Lei,Murai, Yuta,Yoshida, Takuma,Okamoto, Masashi,Masuda, Katsuyoshi,Sakihama, Yasuko,Hashidoko, Yasuyuki,Hatanaka, Yasumaru,Hashimoto, Makoto
, p. 1129 - 1134 (2014)
In this paper we report here a hydrogen/deuterium exchange (H/D exchange) of cross-linkable α-amino acid derivatives with deuterated trifluoromethanesulfonic acid (TfOD). H/D exchange with TfOD was easily applied to o-catechol containing phenylalanine (DOPA) within an hour. A partial H/D exchange was observed for trifluoromethyldiazirinyl (TFMD) phenylalanine derivatives. N-Acetyl-protected natural aromatic α-amino acids (Tyr and Trp) were more effective in H/D exchange than unprotected ones. The N-acetylated TFMD phenylalanine derivative afforded slightly higher H/D exchange than unprotected derivatives. An effective post-deuteration method for cross-linkable α-amino acid derivatives will be useful for the analysis of biological functions of bioactive peptides and proteins by mass spectrometry.
Crosslinking of imprinted proteases to maintain a tailor-made substrate selectivity in aqueous solutions
Peissker, Fabian,Fischer, Lutz
, p. 2231 - 2237 (1999)
A covalent method to keep imprinted properties of proteins stable in aqueous as well as in organic environment is described. To stabilize the ligand induced acceptance for d-configured substrates by α-chymotrypsin or subtilisin Carlsberg, each protein was first vinylated by acylation with itaconic anhydride. Then, the tailoring of the derivatized proteins by precipitation in the presence of N-acetyl-D-tryptophan from an aqueous medium with 1-propanol, and the subsequent crosslinking of the enzyme preparations with ethylene glycol dimethacrylate in cyclohexane was carried out. The crosslinked imprinted proteins (CLIPs) obtained catalyzed the hydrolysis of N-acetyl-D-tryptophan ethyl ester in phosphate buffer and the corresponding back reaction in cyclohexane, respectively. The repeated use of CLIP-α- chymotrypsin in D-ester hydrolysis was demonstrated. Furthermore, this particular CLIP-α-chymotrypsin showed no loss in activity when it subsequently was used in the synthesis of N-acetyl-D-tryptophan ethyl ester in cyclohexane again. In the case of D-ester hydrolysis the reaction rate acceleration (k(enz)/k(nonenz)) was in the same order of magnitude of about 104 -105 mM-1 for the two CLIP-proteases. The results suggest that enzymes tailored by imprinting technique do not lose their induced 'new' property in the presence of water when they are prepared according to the described vinylation/crosslinking method (CLIP technique).
Catecholamine-induced release of nitric oxide from N-nitrosotryptophan derivatives: A non-enzymatic method for catecholamine oxidation
Kytzia, Anna,Korth, Hans-Gert,De Groot, Herbert,Kirsch, Michael
, p. 257 - 267 (2006)
In recent years, interest in the physiological functions of S-nitrosothiols has strongly increased owing to the potential of these compounds to release nitric oxide. In contrast, little is known about similar functions of N-nitrosated (N-terminal-blocked) tryptophan derivatives, which can be also formed at physiological pH. Utilizing N-acetyl-N-nitrosotryptophan (NANT) and N-nitrosomelatonin (NOMela) as model compounds, we have studied their reaction with catechol and catecholamines such as epinephrine and dopamine. In these reactions, NANT was quantitatively converted to N-acetyltryptophan (NAT), and nitric oxide was identified as a volatile product. During this process, ortho-semiquinone-type radical anions deriving from catechol and dopamine, were detected by ESR spectrometry. The catechol radical concentration was about eight times higher under normoxia than under hypoxia and a similar relationship was found for the decay rates of NANT under these conditions. An epinephrine-derived oxidation product, namely adrenochrome, but not a catechol-derived one, was identified. These observations strongly indicate that N-nitrosotryptophan derivatives transfer their nitroso-function to an oxygen atom of the catecholamines, and that the so-formed intermediary aryl nitrite may decompose homolytically with release of nitric oxide, in addition to a competing hydrolysis reaction to yield nitrite and the corresponding catechol. These conclusions were supported by quantum chemical calculations performed at the CBS-QB3 level of theory. Since nitric oxide is non-enzymatically released from N-nitrosotryptophan derivatives on reaction with catecholamines, there might be a possibility for the development of epinephrine-antagonizing drugs in illnesses like hypertension and pheochromocytoma. The Royal Society of Chemistry 2006.
Structure-activity relationship studies of dipeptide-based hepsin inhibitors with Arg bioisosteres
Kwon, Hongmok,Ha, Hyunsoo,Jeon, Hayoung,Jang, Jaebong,Son, Sang-Hyun,Lee, Kiho,Park, Song-Kyu,Byun, Youngjoo
supporting information, (2020/12/25)
Hepsin is a type II transmembrane serine protease (TTSP) associated with cell proliferation and overexpressed in several types of cancer including prostate cancer (PCa). Because of its significant role in cancer progression and metastasis, hepsin is an attractive protein as a potential therapeutic and diagnostic biomarker for PCa. Based on the reported Leu-Arg dipeptide-based hepsin inhibitors, we performed structural modification and determined in vitro hepsin- and matriptase-inhibitory activities. Comprehensive structure-activity relationship studies identified that the p-guanidinophenylalanine-based dipeptide analog 22a exhibited a strong hepsin-inhibitory activity (Ki = 50.5 nM) and 22-fold hepsin selectivity over matriptase. Compound 22a could be a prototype molecule for structural optimization of dipeptide-based hepsin inhibitors.
Tryptophan derivative and application thereof
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Paragraph 0192-0194, (2020/05/30)
The invention discloses a tryptophan derivative or salt acceptable in feed, a stereoisomer, a tautomer, a solvate and a prodrug molecule of the tryptophan derivative. The tryptophan derivative has a structure shown in a formula (I). The tryptophan derivative as shown in the formula (I) and acceptable salt, stereoisomer, tautomer, solvate and prodrug molecules thereof in the feed all show more stable physicochemical properties than tryptophan in a raw material high thermal stability test and a normal temperature stability test of the feed. The content change of the tryptophan derivative does not exceed the acceptable change range of the feed additive or the feed in the test period; moreover, the compounds can effectively improve the growth of animals, feed conversion and other production performances, even have more excellent improvement effects than tryptophan, and can be used as animal feed additives or used for preparing animal feed additives or animal feeds.
