- A colorimetric assay method for measuring D-glutamate cyclase activity
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In mammals, metabolism of free D-glutamate is regulated by D-glutamate cyclase (DGLUCY), which reversibly converts D-glutamate to 5-oxo-D-proline and H2O. Metabolism of these D-amino acids by DGLUCY is thought to regulate cardiac function. In this study, we established a simple, accurate, and sensitive colorimetric assay method for measuring DGLUCY activity. To this end, we optimized experimental procedures for derivatizing 5-oxo-D-proline with 2-nitrophenylhydrazine hydrochloride. 5-Oxo-D-proline was derivatized with 2-nitrophenylhydrazine hydrochloride in the presence of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide as a catalyst to generate the acid hydrazides, whose levels were then determined using a colorimetric method. Under optimized conditions, we examined the sensitivity and accuracy of the colorimetric method and compared our technique with other methods by high-performance liquid chromatography with ultraviolet–visible or fluorescence detection. Moreover, we assessed the suitability of this colorimetric method for measuring DGLUCY activity in biological samples. Our colorimetric method could determine DGLUCY activity with adequate validity and reliability. This method will help to elucidate the relationship among DGLUCY activity, the physiological and pathological roles of D-glutamate and 5-oxo-D-proline, and cardiac function.
- Ariyoshi, Makoto,Hamase, Kenji,Homma, Hiroshi,Katane, Masumi,Matoba, Satoaki,Mita, Masashi,Miyamoto, Tetsuya,Motoda, Risa,Nakayama, Kazuki,Saitoh, Yasuaki,Sakai-Kato, Kumiko,Sekine, Masae,Tateishi, Shuhei
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- Discovery of ABT-957: 1-Benzyl-5-oxopyrrolidine-2-carboxamides as selective calpain inhibitors with enhanced metabolic stability
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Aberrant activation of calpain has been observed in various pathophysiological disorders including neurodegenerative diseases such as Alzheimer's Disease. Here we describe our efforts on ketoamide-based 1-benzyl-5-oxopyrrolidine-2-carboxamides as a novel series of highly selective calpain inhibitors mitigating the metabolic liability of carbonyl reduction. The most advanced compound from this new series, namely A-1212805 (ABT-957, Alicapistat) proceeded to clinical phase I studies.
- Jantos, Katja,Kling, Andreas,Mack, Helmut,Hornberger, Wilfried,Moeller, Achim,Nimmrich, Volker,Lao, Yanbin,Nijsen, Marjoleen
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supporting information
p. 1968 - 1973
(2019/05/29)
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- Structural and enzymatic properties of mammalian D-glutamate cyclase
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D-Glutamate cyclase (DGLUCY) is a unique enzyme that reversibly converts free D-glutamate to 5-oxo-D-proline and H2O. Mammalian DGLUCY is highly expressed in the mitochondrial matrix in the heart, and its downregulation disrupts D-glutamate and/or 5-oxo-D-proline levels, contributing to the onset and/or exacerbation of heart failure. However, detailed characterisation of DGLUCY has not yet been performed. Herein, the structural and enzymatic properties of purified recombinant mouse DGLUCY were examined. The results revealed a dimeric oligomerisation state, and both D-glutamate-to-5-oxo-D-proline and 5-oxo-D-proline-to-D-glutamate reactions were catalysed in a stereospecific manner. Catalytic activity is modulated by divalent cations and nucleotides including ATP and ADP. Interestingly, the presence of Mn2+ completely abolished the 5-oxo-D-proline-to-D-glutamate reaction but stimulated the D-glutamate-to-5-oxo-D-proline reaction. The optimum pH is ~8.0, similar to that in the mitochondrial matrix, and the catalytic efficiency for D-glutamate is markedly higher than that for 5-oxo-D-proline. These findings suggest that DGLUCY functions as a metalloenzyme that degrades D-glutamate in the mitochondrial matrix in mammalian cells. The results also provide insight into the correlation between DGLUCY enzyme activity and the physiological and pathological roles of D-glutamate and 5-oxo-D-proline in cardiac function, which is of relevance to the risk of onset of heart failure.
- Katane, Masumi,Ariyoshi, Makoto,Tateishi, Shuhei,Koiwai, Sachi,Takaku, Kaoruko,Nagai, Kenichiro,Nakayama, Kazuki,Saitoh, Yasuaki,Miyamoto, Tetsuya,Sekine, Masae,Mita, Masashi,Hamase, Kenji,Matoba, Satoaki,Homma, Hiroshi
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- Synthesis of tertiary and quaternary amine derivatives from wood resin as chiral NMR solvating agents
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Chiral tertiary and quaternary amine solvating agents for NMR spectroscopy were synthesized from the wood resin derivative (+)-dehydroabietylamine (2). The resolution of enantiomers of model compounds [Mosher's acid (3) and its n-Bu4N salt (4)] (guests) by (+)-dehydroabietyl-N,N-dimethylmethanamine (5) and its ten different ammonium salts (hosts) was studied. The best results with 3 were obtained using 5 while with 4 the best enantiomeric resolution was obtained using (+)-dehydroabietyl-N,N-dimethylmethanaminium bis(trifluoromethane-sulfonimide) (6). The compounds 5 and 6 showed a 1:1 complexation behaviour between the host and guest. The capability of 5 and 6 to recognize the enantiomers of various α-substituted carboxylic acids and their n-Bu4N salts in enantiomeric excess (ee) determinations was demonstrated. A modification of the RES-TOCSY NMR pulse sequence is described, allowing the enhancement of enantiomeric discrimination when the resolution of multiplets is insufficient.
- Laaksonen, Tiina,Heikkinen, Sami,W?h?l?, Kristiina
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supporting information
p. 20873 - 20886
(2015/12/23)
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- Mapping the substrate selectivity of new hydrolases using colorimetric screening: Lipases from Bacillus thermocatenulatus and Ophiostoma piliferum, esterases from Pseudomonas fluorescens and Streptomyces diastatochromogenes
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Recent advances in biochemistry and molecular biology have simplified the discovery and preparation of new hydrolases. Although these hydrolases might solve problems in organic synthesis, measuring their selectivity, especially enantioselectivity, remains tedious and time consuming. Recently, we developed a colorimetric screening method to measure the enantioselectivity of hydrolases. Here we apply this rapid screening method to map the substrate selectivity of four new hydrolases: lipases from the thermophilic Bacillus thermocatenulatus (DSM 730, BTL2) and a filamentous fungus Ophiostoma piliferum (NRRL 18917, OPL) and esterases from two bacteria, Pseudomonas fluorescens (SIK-W1, esterase I, PFE) and Streptomyces diastatochromogenes (Tue 20, SDE). We screened a general library of 29 substrates and a chiral library of 23 pairs of enantiomers. All four hydrolases catalysed the hydrolysis of unnatural substrates, but the two lipases accepted a broader range of substrates than the two esterases. As expected, the two lipases favoured more hydrophobic substrates, while the two esterases showed a preference for smaller substrates. Several moderately enantioselective reactions were identified for the solketal esters: BTL2, butyrate, E = 7.9 (R); octanoate, E = 4.9 (R) and 3-bromo-2-methyl propionate methyl esters, PFE, E = 12 (S); SDE, E = 5.6 (S). OPL showed low enantioselectivity toward all substrates tested. The current colorimetric screen could not measure the selectivity for several slow-reacting substrates. Traditional screening identified high enantioselectivity of BTL2 and PFE toward one of these slow substrates, 1-phenylethyl acetate (E>50).
- Liu, Andrew Man Fai,Somers, Neil A.,Kazlauskas, Romas J.,Brush, Terry S.,Zocher, Frank,Enzelberger, Markus M.,Bornscheuer, Uwe T.,Horsman, Geoff P.,Mezzetti, Alessandra,Schmidt-Dannert, Claudia,Schmid, Rolf D.
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p. 545 - 556
(2007/10/03)
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- Enantiospecific synthesis of annulated nicotine analogues from D-glutamic acid. 7-Azabicyclo[2.2.1]heptano[2.3.c]pyridines
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The conformationally restricted nicotinoid (1S,4S)-7-methyl-7-azabicyclo[2.2.1]heptano[2,3-c]pyridine dihydrochloride has been prepared enantiospecifically from D-glutamic acid. The method involved a lithium cis-2,6-dimethylpiperidide-mediated intramolecular anionic cyclization of (2S,5R)-N-(tert-butyloxycarbonyl)-5-[3-(4-N-chloropyridinyl]proline methyl ester in tandem with a standard decarboxylation sequence. Reductive amination afforded the desired N-methylated [2.2.1]bicyclonicotinoid. Cyclization of the corresponding iodopyridinylproline methyl ester, obtained via ultrasound-facilitated chloro - iodo exchange, was also effected.
- Lennox,Turner,Rapoport
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p. 7078 - 7083
(2007/10/03)
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- 1,5-dimethyl-4-phenylimidazolidin-2-one-derived iminic glycinimides: Useful new reagents for practical asymmetric synthesis of α-amino acids
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New 1,5-dimethyl-4-phenylimidazolidin-2-one-derived acyclic chiral iminic glycine reagents have been prepared and diastereoselectively alkylated with activated alkyl halides and electrophilic olefins in the presence of lithium chloride under (a) strong bases (LHMDS, KOBu(t)) and low temperature (-78 °C,) conditions; (b) solid-liquid phase-transfer catalysis reaction (LiOH, TBAB, -20 °C) conditions, and (c) in the presence of organic bases (DBU, BEMP, TMG, -20 °C). In the case of dielectrophiles C- and N-alkylation takes place to afford heterocyclic derivatives. Hydrolysis of alkylated products has been carried out (a) in two-step procedures with LiOOH or LiOH followed by acidic hydrolysis or Dowex purification, (b) in one single-step under refluxing water to give the corresponding α-amino acid, (c) in the presence of DBU in methanol to provide N-protected α-amino acids methyl esters, or (d) by a protection-hydrolysis procedure to afford N-Boc-protected α-amino acids. The chiral imidazolidinone has generally been recovered in good yield. This methodology has been shown to be useful for the synthesis of acyclic and heterocyclic (S)- and (R)-α-amino acids.
- Guillena,Najera
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p. 7310 - 7322
(2007/10/03)
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- 12. Approaches to the Synthesis of Cytochalasans; Part 9: A Versatile Concept Leading To All Structural Types of Cytochalasans
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Starting from D-glutamic acid (5), the bicyclic compounds 4a and 4b were synthesized via 17 (Schemes 1 and 2).The reaction leading to 4g and 4h with LiCuPh2 was not successful.But treatment of the N-protected model lactams 19, 21, and 22 with Li2Cu(CN)Ph2 gave the amino ketones 24, 26, and 26, respectively (Scheme 3).The desired compound 23 was obtained from 20.Conversion of the unprotected lactams 28, 31, and 32 gave the phenyl derivative 34 in excellent yields.Ester 35 was transformed to the α-amino-γ-oxo-acid derivative 36.This conversion opens a novel access to this type of compounds.
- Ackermann, Jean,Matthes, Michael,Tamm, Christoph
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p. 122 - 132
(2007/10/02)
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- Effect of the Side Chain on the Racemization of Amino Acids in Aqueous Solution
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The rate of racemization of 13 amino acids possessing hydroxy, carboxy, alkoxy, carboalkoxy, alkyl, aryl, and thioether side chains were compared.Reaction conditions were identical for all amino acids studied.Gas chromatography was used to determine the percent of D isomer present.Hydroxy amino acids racemized most rapidly, but conversion to an ether function reduced the rate considerably.The increased racemization rate of methionine (R = CH2CH2SCH3) over Ala (R = CH3) has been attributed to orbital overlap from the sulfur.Asp racemized faster than Glu, α-aminoadipic acid, and pyroglutamic acid. β- and γ-monomethyl esters of aspartic and glutamic acids, respectively, racemized only slightly faster than the corresponding free acids.The slight increase in rate appears attributable to a solvent change brought on by ester hydrolysis.Under the reaction conditions, pH 8 and 140 deg C, hydrolysis of the esters competed favorably with racemization at the methine carbon.The relatively lower racemization rate observed in the case of Glu compared with Asp resulted from the slow formation of pyroglutamic acid.Pyroglutamic acid racemized at a considerably slower rate than acidic amino acids.The differences in the racemization rates with changes in the R group are discussed in terms of several factors, including intramolecular reactions, direct field effects, orbital overlap, and solvation effects, as well as inductive, resonance, and steric factors.
- Smith, Grant Gill,Reddy, G. Vanita
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p. 4529 - 4535
(2007/10/02)
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- Heterocyclic Prostaglandins. V. Synthesis of (12R,15S)-(-)-11-Deoxy-8-azaprostaglandin E1 and Related Compounds
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The synthesis of (12R,15S)-(-)-11-deoxy-8-azaprostaglandin E1 ((R)-1a) and three diastereomers ((R)-2a, (S)-1a, and (S)-2a) starting from optically active pyroglutamic acid ((R)-3 and (S)-3) is reported.Esterification of (R)-3 and NaBH4 reduction gave (R)-(-)-5-hydroxymethyl-2-pyrrolidinone ((R)-5).Ethoxyethylation of (R)-5 and N-alkylation with methyl 7-bromoheptanoate, followed by acid treatment, provided (R)-hydroxymethyl pyrrolidinone ((R)-8).The Collins oxidation of (R)-8 gave (R)-(-)-methyl 7-(5-formyl-2-oxo-1-pyrrolidine)heptanoate ((R)-9), which served as a key intermediate.The Wittig reaction of (R)-9 and dimethyl 2-oxoheptylphosphonate gave the (R)-enone ((R)-10a) which was converted to the (12R,15S)-enol ((R)-11a) and (12R,15R)-enol ((R)-12a) by NaBH4 reduction.Alkaline hydrolysis of (R)-11a and (R)-12a gave (R)-1a and (R)-2a in high yields.Similarly, the (S)-aldehyde ((S)-9) was prepared from (S)-3 and converted to the (12S,15S)-acid ((S)-1a) and (12S,15R)-acid ((S)-2a) by the same sequence of reactions used for the (R)-series.Some (12R,15S)-acid derivatives ((R)-1b-g) with a modified ω-chain were also synthesized.These analogs ((R)-1b-g) were also prepared from (R)-9 via synthetic sequences similar to that described above.Keywords - heterocyclic prostaglandin; (12R,15S)-(-)-11-deoxy-8-azaprostaglandin E1; (12R,15R)-(-)-11-deoxy-8-azaprostaglandin E1; (12S,15S)-(+)-11-deoxy-8-azaprostaglandin E1; (12S,15R)-(+)-11-deoxy-8-azaprostaglandin E1; (R)-(-)-methyl 7-(5-formyl-2-oxo-1-pyrrolidine)heptanoate; (S)-(+)-methyl 7-(5-formyl-2-oxo-1-pyrrolidine)heptanoate
- Saijo, Shigeyoshi,Wada, Masao,Himizu, Jun-ichi,Ishida, Akihiko
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p. 1449 - 1458
(2007/10/02)
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