16422-27-8Relevant academic research and scientific papers
Low mass MS/MS fragments of protonated amino acids used for distinction of their 13C- isotopomers in metabolic studies
Ma, Xin,Dagan, Shai,Somogyi, Arpad,Wysocki, Vicki H.,Scaraffia, Patricia Y.
, p. 622 - 631 (2013)
Glu, Gln, Pro, and Ala are the main amino acids involved in ammonia detoxification in mosquitoes. In order to develop a tandem mass spectrometry method (MS2) to monitor each carbon of the above isotopically-labeled 13C-amino acids for metabolic studies, the compositions and origins of atoms in fragments of the protonated amino acid should be first elucidated. Thus, various electrospray (ESI)-based MS2 tools were employed to study the fragmentation of these unlabeled and isotopically-labeled amino acids and better understand their dissociation pathways. A broad range of fragments, including previously-undescribed low m/z fragments was revealed. The formulae of the fragments (from m/z 130 down to m/z 27) were confirmed by their accurate masses. The structures and conformations of the larger fragments of Glu were also explored by ion mobility mass spectrometry (IM-MS) and gas-phase hydrogen/deuterium exchange (HDX) experiments. It was found that some low m/z fragments (m/z 27-30) are common to Glu, Gln, Pro, and Ala. The origins of carbons in these small fragments are discussed and additional collision induced dissociation (CID) MS2 fragmentation pathways are proposed for them. It was also found that small fragments (≤m/z 84) of protonated, methylated Glu, and methylated Gln are the same as those of the underivatized Glu and Gln. Taken together, the new approach of utilizing low m/z fragments can be applied to distinguish, identify, and quantify 13C-amino acids labeled at various positions, either in the backbone or side chain. [Figure not available: see fulltext.]
Alkaloids from the mushroom pseudobaeospora pyrifera, pyriferines A-C
Dang, Ngoc Quang,Spiteller, Peter,Porzel, Andrea,Schmidt, Juergen,Geissler, Torsten,Arnold, Norbert,Wessjohann, Ludger
, p. 1620 - 1622 (2008)
Three novel alkaloids (1-3), named pyriferines A-C, were isolated from fruiting bodies of Pseudobaeospora pyrifera. They possess an unusual eight-membered N/O-acetal ring, derived from L-glutamic acid, that is connected to an enolized 1,3-diketo moiety. The structures were determined by spectroscopic methods, and the absolute configuration of the glutamic acid moiety was established using GC-MS after Mosher-type derivatization.
Initial in vitro and in vivo evaluation of a novel CCK2R targeting peptide analog labeled with lutetium-177
Gust, Ronald,H?rmann, Anton Amadeus,H?rmann, Nikolas,Klingler, Maximilian,Rezaeianpour, Maliheh,Shahhosseini, Soraya,von Guggenberg, Elisabeth
, (2020)
Targeting of cholecystokinin-2 receptor (CCK2R) expressing tumors using radiolabeled minigastrin (MG) analogs is hampered by rapid digestion of the linear peptide in vivo. In this study, a new MG analog stabilized against enzymatic degradation was investigated in preclinical studies to characterize the metabolites formed in vivo. The new MG analog DOTA-DGlu-Pro -Tyr-Gly-Trp-(N-Me)Nle-Asp-1Nal-NH2 comprising site-specific amino acid substitutions in position 2, 6 and 8 and different possible metabolites thereof were synthesized. The receptor interaction of the peptide and selected metabolites was evaluated in a CCK2R-expressing cell line. The enzymatic stability of the 177Lu-labeled peptide analog was evaluated in vitro in different media as well as in BALB/c mice up to 1 h after injection and the metabolites were identified based on radio-HPLC analysis. The new radiopeptide showed a highly increased stability in vivo with >56% intact radiopeptide in the blood of BALB/c mice 1 h after injection. High CCK2R affinity and cell uptake was confirmed only for the intact peptide, whereas enzymatic cleavage within the receptor specific C-terminal amino acid sequence resulted in complete loss of affinity and cell uptake. A favorable biodistribution profile was observed in BALB/c mice with low background activity, preferential renal excretion and prolonged uptake in CCK2R-expressing tissues. The novel stabilized MG analog shows high potential for diagnostic and therapeutic use. The radiometabolites characterized give new insights into the enzymatic degradation in vivo.
Nematicidal anthranilic acid derivatives from Laccaria species
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Three undescribed natural products, the anthranilic acid derivatives laccanthrilic acids A, B, and C, as well as the known (3S)-1,2,3,4-tetrahydro-3-β-carboline-3-carboxylic acid were isolated from fruiting bodies of Laccaria laccata. The structures were established by 1D and 2D NMR spectroscopy, HR-(+)-ESIMS and chemical synthesis. The absolute configuration of laccanthrilic acids A and B was determined by GC-MS after hydrolytic cleavage and derivatisation of the resulting glutamic acid with methanol and Mosher's reagent and subsequent comparison with authentic synthetic samples of known absolute configuration. The absolute configuration of laccanthrilic acid C was determined by comparison of the CD spectra of laccanthrilic acids B and C with each other. Metabolic profiling of related species showed that the compounds are common in the genus Laccaria. Laccanthrilic acid B exhibited moderate nematicidal effects against Caenorhabditis elegans, which might explain to some degree the beneficial role of these fungi for the growth and survival of their host plants.
Exploring the ability of dihydropyrimidine-5-carboxamide and 5-benzyl-2,4-diaminopyrimidine-based analogues for the selective inhibition of L. major dihydrofolate reductase
Bibi, Maria,Qureshi, Naveeda Akhter,Sadiq, Abdul,Farooq, Umar,Hassan, Abbas,Shaheen, Nargis,Asghar, Irfa,Umer, Duaa,Ullah, Azmat,Khan, Farhan A.,Salman, Muhammad,Bibi, Ahtaram,Rashid, Umer
, (2020/11/16)
To tackle leishmaniasis, search for efficient therapeutic drug targets should be pursued. Dihydrofolate reductase (DHFR) is considered as a key target for the treatment of leishmaniasis. In current study, we are interested in the design and synthesis of selective antifolates targeting DHFR from L. major. We focused on the development of new antifolates based on 3,4-dihydropyrimidine-2-one and 5-(3,5-dimethoxybenzyl)pyrimidine-2,4-diamine motif. Structure activity relationship (SAR) studies were performed on 4-phenyl ring of dihydropyrimidine (26–30) template. While for 5-(3,5-dimethoxybenzyl)pyrimidine-2,4-diamine, the impact of different amino acids (valine, tryptophan, phenylalanine, and glutamic acid) and two carbon linkers were explored (52–59). The synthesized compounds were assayed against LmDHFR. Compound 59 with the IC50 value of 0.10 μM appeared as potent inhibitors of L. major. Selectivity for parasite DHFR over human DHFR was also determined. Derivatives 55–59 demonstrated excellent selectivity for LmDHFR. Highest selectivity for LmDHFR was shown by compounds 56 (SI = 84.5) and 58 (SI = 87.5). Compounds Antileishmanial activity against L. major and L. donovani promastigotes was also performed. To explore the interaction pattern of the synthesized compounds with biological macromolecules, the docking studies were carried out against homology modelled LmDHFR and hDHFR targets.
A General Stereocontrolled Synthesis of Opines through Asymmetric Pd-Catalyzed N-Allylation of Amino Acid Esters
Albat, Dominik,Neud?rfl, J?rg-Martin,Schmalz, Hans-Günther
supporting information, p. 2099 - 2102 (2021/07/22)
A stereo-divergent synthesis of natural and unnatural opines in stereochemically pure form is based on the direct palladium-catalyzed N-allylation of α-amino acid esters (up to 97 % ee or 99 : 1 d.r.) using methyl (E)-2-penten-4-yl carbonate in the presence of only 1 mol% of a catalyst, prepared in-situ from the C2-symmetric diphosphine iPr-MediPhos and [Pd(allyl)Cl]2. Selected target compounds (incl. a derivative of the drug enalapril) were efficiently obtained from the N-allylated intermediates by oxidative cleavage (ozonolysis) of the allylic C=C bond under temporary N-Boc-protection.
Selenolysine: A New Tool for Traceless Isopeptide Bond Formation
Dardashti, Rebecca Notis,Kumar, Shailesh,Sternisha, Shawn M.,Reddy, Post Sai,Miller, Brian G.,Metanis, Norman
supporting information, p. 4952 - 4957 (2020/04/07)
Despite their biological importance, post-translationally modified proteins are notoriously difficult to produce in a homogeneous fashion by using conventional expression systems. Chemical protein synthesis or semisynthesis offers a solution to this problem; however, traditional strategies often rely on sulfur-based chemistry that is incompatible with the presence of any cysteine residues in the target protein. To overcome these limitations, we present the design and synthesis of γ-selenolysine, a selenol-containing form of the commonly modified proteinogenic amino acid, lysine. The utility of γ-selenolysine is demonstrated with the traceless ligation of the small ubiquitin-like modifier protein, SUMO-1, to a peptide segment of human glucokinase. The resulting polypeptide is poised for native chemical ligation and chemoselective deselenization in the presence of unprotected cysteine residues. Selenolysine's straightforward synthesis and incorporation into synthetic peptides marks it as a universal handle for conjugating any ubiquitin-like modifying protein to its target.
N-Pyrazinoyl substituted amino acids as potential antimycobacterial agents-the synthesis and biological evaluation of enantiomers
Bárta, Pavel,Dole?al, Martin,Horá?ek, Ond?ej,Jand'Ourek, Ond?ej,Janou?ek, Ji?í,Juhás, Martin,Kone?ná, Klára,Ku?era, Radim,Ku?erová, Lucie,Kubí?ek, Vladimír,Kune?, Ji?í,Paterová, Pavla,Zitko, Jan
, (2020/04/09)
Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis (Mtb), each year causing millions of deaths. In this article, we present the synthesis and biological evaluations of new potential antimycobacterial compounds containing a fragment of the first-line antitubercular drug pyrazinamide (PZA), coupled with methyl or ethyl esters of selected amino acids. The antimicrobial activity was evaluated on a variety of (myco)bacterial strains, including Mtb H37Ra, M. smegmatis, M. aurum, Staphylococcus aureus, Pseudomonas aeruginosa, and fungal strains, including Candida albicans and Aspergillus flavus. Emphasis was placed on the comparison of enantiomer activities. None of the synthesized compounds showed any significant activity against fungal strains, and their antibacterial activities were also low, the best minimum inhibitory concentration (MIC) value was 31.25 μM. However, several compounds presented high activity against Mtb. Overall, higher activity was seen in derivatives containing l-amino acids. Similarly, the activity seems tied to the more lipophilic compounds. The most active derivative contained phenylglycine moiety (PC-d/l-Pgl-Me, MIC 1.95 μg/mL). All active compounds possessed low cytotoxicity and good selectivity towards Mtb. To the best of our knowledge, this is the first study comparing the activities of the d- and l-amino acid derivatives of pyrazinamide as potential antimycobacterial compounds.
Method for synthesizing glutamic acid-1-methyl ester-5-tert-butyl ester
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Paragraph 0027; 0028, (2019/04/13)
The invention discloses a method for synthesizing glutamic acid-1-methyl ester-5-tert-butyl ester. The method comprises the following steps: generating dimethyl glutamate by using glutamic acid as aninitial raw material in methyl alcohol under the effect of thionyl chloride; reacting the dimethyl glutamate with triphenylchloromethane to generate dimethyl glutamate with triphenylmethyl protected amino; taking off methyl ester on the 5 position of the dimethyl glutamate with triphenylmethyl protected amino under the effect of sodium hydroxide to generate triphenylmethyl-glutamic acid-1-methyl ester; reacting the triphenylmethyl-glutamic acid-1-methyl ester-5-tert-butyl ester with trichloroacetic imine tert-butyl ester to generate triphenylmethyl-glutamic acid-1-methyl ester-5-tert-butyl ester, adding a small amount of triisopropylsilane into the triphenylmethyl-glutamic acid-1-methyl ester-5-tert-butyl ester in a low-concentration dichloromethane trifluoroacetate solution to take off triphenylmethyl to generate the glutamic acid-1-methyl ester-5-tert-butyl ester. The method is simple in operation, has few byproduct which can be extremely easy to treat and high product yield, and cansolve the problem of large operation difficulty in an existing synthesizing method.
NOVEL PYRROLO-LACTONE AND PYRROLE COMPOUNDS INDUCING CELLULAR GLUTATHIONE RECOVERY EFFECT AGAINST REACTIVE OXYGEN SPECIES, AND METHOD FOR PREPARING THE SAME
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Paragraph 0102-0106; 0124; 0128; 0153; 0157, (2019/05/10)
The present invention provides: a novel pyrrolo-lactone compound, which can be used as an improved pain therapeutic agent containing various substituents by using glucose and ribose as reducing sugars and conducting a reaction with various kinds of natural and unnatural amino acids; and novel pyrrolo compounds produced during a process of manufacturing the same. The novel pyrrolo-lactone and pyrrole compounds are substances which can be used as improved pain therapeutic agent by having increased restoration ability of glutathione in living cells against reactive oxygen species.COPYRIGHT KIPO 2019
