- Recharacterization of the mammalian cytosolic type 2 (R)-β-hydroxybutyrate dehydrogenase as 4-oxo-L-proline reductase (EC 1.1.1.104)
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Early studies revealed that chicken embryos incubated with a rare analog of L-proline, 4-oxo-L-proline, showed increased levels of the metabolite 4-hydroxy-L-proline. In 1962, 4-oxo-L-proline reductase, an enzyme responsible for the reduction of 4-oxo-L-proline, was partially purified from rabbit kidneys and characterized biochemically. However, only recently was the molecular identity of this enzyme solved. Here, we report the purification from rat kidneys, identification, and biochemical characterization of 4-oxo-L-proline reductase. Following mass spectrometry analysis of the purified protein preparation, the previously annotated mammalian cytosolic type 2 (R)-βhydroxybutyrate dehydrogenase (BDH2) emerged as the only candidate for the reductase. We subsequently expressed rat and human BDH2 in Escherichia coli, then purified it, and showed that it catalyzed the reversible reduction of 4-oxo-L-proline to cis-4-hydroxy-L-proline via chromatographic and tandem mass spectrometry analysis. Specificity studies with an array of compounds carried out on both enzymes showed that 4-oxo-L-proline was the best substrate, and the human enzyme acted with 12,500-fold higher catalytic efficiency on 4-oxo-L-proline than on (R)-β-hydroxybutyrate. In addition, human embryonic kidney 293T (HEK293T) cells efficiently metabolized 4-oxo-L-proline to cis-4-hydroxy-L-proline, whereas HEK293T BDH2 KO cells were incapable of producing cis-4-hydroxy-L-proline. Both WT and KO HEK293T cells also produced trans-4-hydroxy-L-proline in the presence of 4-oxo-L-proline, suggesting that the latter compound might interfere with the trans-4-hydroxy-L-proline breakdown in human cells. We conclude that BDH2 is a mammalian 4-oxo-L-proline reductase that converts 4-oxo-L-proline to cis-4-hydroxy-L-proline and not to trans-4-hydroxy-L-proline, as originally thought. We also hypothesize that this enzyme may be a potential source of cis-4-hydroxy-L-proline in mammalian tissues.
- Bozko, Maria,Drozak, Jakub,Jagielski, Adam K.,Kocdemir, Kubra,Kwiatkowski, Sebastian,Witecka, Apolonia,Zarod, Michal
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- Discovery of New Fe(II)/α-Ketoglutarate-Dependent Dioxygenases for Oxidation of l-Proline
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Genome mining for novel Fe(II)/α-ketoglutarate-dependent dioxygenases (αKGDs) to expand the enzymatic repertoire in the oxidation of l-proline is reported. Through clustering of proteins, we predicted regio- and stereoselectivity in the hydroxylation reaction and validated this hypothesis experimentally. Two novel byproducts in the reactions with enzymes from Bacillus cereus and Streptomyces sp. were isolated, and the structures were determined to be a 3,4-epoxide and a 3,4-diol, respectively. The mechanism for the formation of the epoxide was investigated by performing an 18O-labeling experiment. We propose that the mechanism proceeds via initial cis-3-hydroxylation followed by ring closure. A biocatalytic step was run on subgram quantities of starting material without any significant optimization of the conditions. However, the substrate concentration was 40-fold higher than the usual reported titers for recombinant P450-mediated hydroxylations, showing the synthetic potential of αKGDs on a preparative scale.
- Dussauge, Solene,Moore, Charles,Snajdrova, Radka,Tassano, Erika,Vargas, Alexandra
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supporting information
(2022/02/09)
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- Studies on the selectivity of proline hydroxylases reveal new substrates including bicycles
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Studies on the substrate selectivity of recombinant ferrous-iron- and 2-oxoglutarate-dependent proline hydroxylases (PHs) reveal that they can catalyse the production of dihydroxylated 5-, 6-, and 7-membered ring products, and can accept bicyclic substrates. Ring-substituted substrate analogues (such hydroxylated and fluorinated prolines) are accepted in some cases. The results highlight the considerable, as yet largely untapped, potential for amino acid hydroxylases and other 2OG oxygenases in biocatalysis.
- Smart, Tristan J.,Hamed, Refaat B.,Claridge, Timothy D.W.,Schofield, Christopher J.
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supporting information
(2019/11/26)
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- Discovery of new A- and B-type laxaphycins with synergistic anticancer activity
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Two new cyclic lipopeptides termed laxaphycins B4 (1) and A2 (2) were discovered from a collection of the marine cyanobacterium Hormothamnion enteromorphoides, along with the known compound laxaphycin A. The planar structures were solved based on a combined interpretation of 1D and 2D NMR data and mass spectral data. The absolute configurations of the subunits were determined by chiral LC-MS analysis of the hydrolysates, advanced Marfey's analysis and 1D and 2D ROESY experiments. Consistent with similar findings on other laxaphycin A- and B-type peptides, laxaphycin B4 (1) showed antiproliferative effects against human colon cancer HCT116 cells with IC50 of 1.7 μM, while laxaphycins A and A2 (2) exhibited weak activities. The two major compounds isolated from the sample, laxaphycins A and B4, were shown to act synergistically to inhibit the growth of HCT116 colorectal cancer cells.
- Cai, Weijing,Matthew, Susan,Chen, Qi-Yin,Paul, Valerie J.,Luesch, Hendrik
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p. 2310 - 2319
(2018/04/02)
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- Peptide Tyrosinase Activators
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Peptides that increase melanin synthesis are provided. These peptides include pentapeptides YSSWY, YRSRK, and their variants. The peptides may activate the enzymatic activity of tyrosinase to increase melanin synthesis. The pharmaceutical, cosmetic, and other compositions including the peptides are also provided. The methods of increasing melanin production in epidermis of a subject are provided where the methods include administering compositions comprising an amount of one or more peptides effective to increase the melanin production. The methods also include treating vitiligo or other hypopigmentation disorders with compositions including one or more peptides.
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- Substrate specificity and stereoselectivity of two Sulfolobus 2-keto-3-deoxygluconate aldolases towards azido-substituted aldehydes
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The 2-keto-3-deoxygluconate aldolases (KDGAs) isolated from Sulfolobus species convert pyruvate and glyceraldehyde reversibly into 2-keto-3-deoxygluconate and -galactonate. As a result of their high thermostability and activity on nonphosphorylated substrates, KDGA enzymes have potential as biocatalysts for the production of building blocks for fine chemical and pharmaceutical applications. Up to now, wild-type enzymes have only shown moderate stereocontrol for their natural reaction. However, if a set of azido-functionalized aldehydes were applied as alternative acceptors in the reaction with pyruvate, the stereoselectivity was strongly increased to give enantiomeric or diastereomeric excess values up to 97 %. The Sulfolobus acidocaldarius KDGA displayed a higher stereoselectivity than Sulfolobus solfataricus KDGA for all tested reactions. The azido-containing products are useful chiral intermediates in the synthesis of nitrogen heterocycles. Taming the wild-type: Two 2-keto-3-deoxygluconate aldolases from Sulfolobus species readily couple azido-substituted aldehydes to pyruvate in a stereoselective manner. The resulting compounds yield chiral nitrogen heterocycles upon reduction.
- Schurink, Marloes,Wolterink-Van Loo, Suzanne,Van Der Oost, John,Sonke, Theo,Franssen, Maurice C. R.
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p. 1073 - 1081
(2014/05/06)
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- PROCESS FOR PRODUCING SOLID AMINO ACID
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The problem to be solved by the present invention is to ea lily and efficiently produce an amino acid having 2 to 7 carbon atoms as a high-purity solid without complicated operation, which is useful as a synthetic intermediate for medicines or agrochemicals. The present invention is characterized in comprising a step of precipitating solid amino acid with high purity. In the present invention, the by-produced salt composed of the sulfonic acid and the amine was removed to the mother liquor by reacting an amine with a sulfonic acid salt of amino acid in an aprotic polar solvent, or by reacting a sulfonic acid with an amine salt of amino acid in an aprotic polar solvent. The sulfonic acid salt of amino acid, for example, may be produced by reacting a N-(tert-butoxycarbonyl) amino acid with a sulfonic acid, or by reacting an amino acid tert-butyl ester with a sulfonic acid.
- -
-
Paragraph 0055
(2014/12/09)
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- Biochemical characterisation and assessment of fibril-forming ability of collagens extracted from Bester sturgeon Huso huso × Acipenser ruthenus
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Collagens purified from Bester sturgeon organs were characterised biochemically, and their fibril-forming abilities and fibril morphologies formed in vitro clarified. Yields of collagens were 2.1%, 11.9%, 0.4%, 18.1%, 0.4%, 0.8% and 0.03% (collagen dry weight/tissue wet weight) from scales, skin, muscle, swim bladder, digestive tract, notochord and snout cartilage, respectively. Using SDS-PAGE and amino acid composition analyses, collagens from scales, skin, muscle, the swim bladder and digestive tract were characterised as type I, and collagens from the notochord and snout cartilage as type II. Denaturation temperatures of the collagens, measured using circular dichroism, were 29.6, 26.8, 29.0, 32.9, 31.6 and 36.3 °C in scales, skin, muscle, swim bladder, digestive tract, and notochord, respectively. For fibril formation, swim bladder and skin collagen showed a more rapid rate of increase in turbidity, a shorter time to attain the maximum turbidity, and formed thicker fibrils compared with porcine tendon type I collagen.
- Zhang, Xi,Ookawa, Mika,Tan, Yongkai,Ura, Kazuhiro,Adachi, Shinji,Takagi, Yasuaki
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p. 305 - 312
(2014/05/06)
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- Pneumocandin biosynthesis: Involvement of a trans-selective proline hydroxylase
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Echinocandins are cyclic nonribosomal hexapeptides based mostly on nonproteinogenic amino acids and displaying strong antifungal activity. Despite previous studies on their biosynthesis by fungi, the origin of three amino acids, trans-4-and trans-3-hydroxyproline, as well as trans-3-hydroxy-4-meth-ylproline, is still unknown. Here we describe the identification, overexpression, and characterization of GloF, the first eukaryot-ic a-ketoglutarate/FeII-dependent proline hydroxylase from the pneumocandin biosynthesis cluster of the fungus Glarea loz-oyensis ATCC 74030. In in vitro transformations with L-proline, GloF generates trans-4- and trans-3-hydroxyproline simultaneously in a ratio of 8:1; the latter reaction was previously unknown for proline hydroxylase catalysis. trans-4-Methyl-L-proline is converted into the corresponding trans-3-hydroxypro-line. All three hydroxyprolines required for the biosynthesis of the echinocandins pneumocandins A0 and B0 in G. lozoyensis are thus provided by GloF. Sequence analyses revealed that GloF is not related to bacterial proline hydroxylases, and none of the putative proteins with high sequence similarity in the databases has been characterized so far.
- Houwaart, Stefanie,Youssar, Loubna,Hüttel, Wolfgang
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p. 2365 - 2369
(2015/03/03)
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- Meteorites as catalysts for prebiotic chemistry
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From outer space: Twelve meteorite specimens, representative of their major classes, catalyse the synthesis of nucleobases, carboxylic acids, aminoacids and low-molecular-weight compounds from formamide (see figure). Different chemical pathways are identified, the yields are high for a prebiotic process and the products come in rich and composite panels.
- Saladino, Raffaele,Botta, Giorgia,Delfino, Michela,Di Mauro, Ernesto
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p. 16916 - 16922
(2014/01/06)
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- Chiral imprinting with amino acids of ordered mesoporous silica exhibiting enantioselectivity after calcination
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Chiral ordered mesoporous silica (COMS) was synthesized in basic media by combining tetraethyl orthosilicate and quaternized aminosilane (with a templating role) silica sources together with four different standard amino acids (arginine, histidine, isoleucine, and proline). Besides the hexagonal MCM-41-type structure, narrow pore size distribution, and high specific surface area, it was found that these solids have potential for enantiomeric separation because of the transference of chirality from the amino acid to the silica. This is illustrated by the resolution of several racemic mixtures (those of proline, isoleucine, trans-4-hydroxyproline, pipecolic acid, valine, leucine, and phenylglycine) with the calcined COMS prepared with l-proline. The opposite behavior observed in induced circular dichroism experiments with calcined COMS, obtained using both enantiomers of proline, confirmed their chiral nature. The high number and variety of existing amino acids, and chiral organic compounds in general, makes these ordered silicas attractive for the production of enantiopure substances.(Figure Presented)
- Lacasta, Susana,Sebastian, Victor,Casado, Clara,Mayoral, Alvaro,Romero, Pilar,Larrea, Angel,Vispe, Eugenio,Lopez-Ram-De-Viu, Pilar,Uriel, Santiago,Coronas, Joaquin
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scheme or table
p. 1280 - 1287
(2012/02/15)
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- A simple procedure for selective hydroxylation of L -proline and l -pipecolic acid with recombinantly expressed proline hydroxylases
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Due to their diverse regio- and stereoselectivities, proline hydroxylases provide a straightforward access to hydroxprolines and other hydroxylated cylic amino acids, valuable chiral building blocks for chemical synthesis, which are often not available at reasonable expense by classical chemical synthesis. As yet, the application of proline hydroxylases is limited to a sophisticated industrial process for the production of two hydroxyproline isomers. This is mainly due to difficulties in their heterologues expression, their limited in vitro stability and complex product purification procedures. Here we describe a facile method for the production of cis-3-, cis-4- and trans-4-proline hydroxylase, and their application for the regio- and stereoselective hydroxylation of L-proline and its six-membered ring homologue l-pipecolic acid. Since in vitro catalysis with these enzymes is not very efficient and conversions are restricted to the milligram scale, an in vivo procedure was established, which allowed a quantitative conversion of 6 mM l-proline in shake flask cultures. After facile product purification via ion exchange chromatography, hydroxyprolines were isolated in yields of 35-61% (175-305 mg per flask). L-Pipecolic acid was converted with the isolated enzymes to prove the selectivities of the reactions. In transformations with optimized iron(II) concentration, conversions of 17-68% to hydroxylated products were achieved. The regio- and stereochemistry of the products was determined by NMR techniques. To demonstrate the applicability of the preparative in vivo approach for non-physiological substrates, L-pipecolic acid was converted with an E. coli strain producing trans-4-proline hydroxylase to trans-5-hydroxy-L-pipecolic acid in 61% yield. Thus, a synthetically valuable group of biocatalysts was made readily accessible for application in the laboratory without a need for special equipment or considerable development effort.
- Klein, Christian,Huettel, Wolfgang
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experimental part
p. 1375 - 1383
(2011/06/26)
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- Synthesis of fmoc-pro-hyp(TBDPS)-gly-OH and its application as a versatile building block for the preparation of collagen model peptides
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The efficient synthesis of the tripeptidic building block Fmoc-Pro-Hyp(TBDPS)-Gly-OH and its application for the preparation of collagen model peptides (CMPs) has been achieved. The silyl ether protecting group prevents undesired side reactions during the
- Erdmann, Roman S.,Wennemers, Helma
-
experimental part
p. 143 - 147
(2009/06/19)
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- Enzymatic synthesis of cyclic amino acids by N-methyl-l-amino acid dehydrogenase from Pseudomonas putida
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A new enzymatic system for the synthesis of enantiomerically pure cyclic amino acids (CAA) from the corresponding diamino acids or racemic CAA is described. α,ω-Diamino acids were oxidized to α-keto acids with amino acid oxidases (AAO). The α-keto acids were spontaneously transformed into cyclic imino acids in the reaction medium. The resulting imines were reduced to the l-form CAA with N-methyl-l-amino acid dehydrogenase (NMAADH) from Pseudomonas putida ATCC12633 using NADPH as a cofactor. l-Form CAA were also obtained from racemic CAA using d-amino-acid oxidase and NMAADH. Using this method, a new compound [1,4]-thiazepane-3-carboxylic acid (Fig. 1) was synthesized from aminopropylcystein.
- Yasuda, Mari,Ueda, Makoto,Muramatsu, Hisashi,Mihara, Hisaaki,Esaki, Nobuyoshi
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p. 1775 - 1779
(2007/10/03)
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- Process for producing alpha 2,3/ alpha 2,8-sialyltransferase and sialic acid-containing complex sugar
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The present invention can provide a process for producing a protein having α2,3/α2,8-sialyltransferase activity using a transformant comprising a DNA encoding a protein having α2,3/α2,8-sialyltransferase activity derived from a microorganism belonging to the genus Pasteurella and a process for producing a sialic acid-containing complex carbohydrate using a transformant capable of producing a protein having α2,3/α2,8-sialyltransferase activity derived from a microorganism.
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- Anti-heparin peptides
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The invention concerns a compound exhibiting an anti-heparin activity, of formula Z Bm ! (AXA)x Bn ! (AXA)y Bo (AXA)z Bp, the diagnostic reagents comprising it and the use of said compound in an in vitro diagnostic test of a medicine for anti-heparin activity.
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- Gene recombinant antibody and antibody fragment thereof
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A recombinant antibody or the antibody fragment thereof which specifically reacts with an extracellular domain of human CCR4; a DNA which encodes the recombinant antibody or the antibody fragment thereof; a method for producing the recombinant antibody or the antibody fragment thereof; a method for immunologically detecting CCR4, a method for immunologically detecting a cell which expressed CCR4 on the cell surface, a method for depleting a cell which expresses CCR4 on the cell surface, and a method for inhibiting production of Th2 cytokine, which comprise using the recombinant antibody according or antibody fragment thereof; a therapeutic or diagnostic agent for Th2-mediated immune diseases; and a therapeutic or diagnostic agent for a blood cancer.
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-
- COSMETICS
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The present invention relates to skin aging inhibitors and/or skin quality-improving agents comprising hydroxyproline, its N-acyl derivatives or salts thereof, and cosmetic compositions for inhibiting skin aging and/or improving skin quality comprising said skin aging inhibitors and/or skin quality-improving agents.
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- Process for producing trans-4-hydroxy-L-proline
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An industrially applicable process for producing trans-4-hydroxy-L-proline, which is useful as a raw material for medicines or as an additive to foods. In the process, L-proline is converted into trans-4-hydroxy-L-proline in the presence of an enzyme source which is derived from a microorganism belonging to the genus Dactylosporangium, Amycolatopsis or Streptomyces and which catalyzes the hydroxylation of L-proline into trans-4-hydroxy-L-proline, a divalent iron ion and 2-ketoglutaric acid, in an aqueous medium, and the produced trans-4-hydroxy-L-proline is collected from the aqueous medium. Also provided is a novel enzyme L-proline-4-hydroxylase which is useful for the process, a gene of L-proline-4-hydroxylase which is useful for the process, a transformant containing the gene, and a process for producing L-proline-4-hydroxylase using the transformant. In addition, provided is a process for producing L-proline-4-hydroxylase using the transformant which contains the gene and has a reinforced proline biosynthesis activity.
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- Amine compounds and combinatorial libraries comprising same
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The present invention provides monocyclic, bicyclic and oligomeric amine compounds with at least two sites of diversity. These compounds are formed from monocyclic scaffolds which can be cyclized to form bicyclic amine scaffolds. These can then be reacted with building blocks to form the amine compounds of the invention. This invention further provides libraries or monocyclic, bicyclic and oligomeric amine compounds. Also provided are methods for preparing monocyclic, bicyclic and oligomeric amine compounds and libraries thereof. The present invention also provides pharmaceutical compositions of the monocyclic, bicyclic and oligomeric amine compounds.
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- FR901469, a novel antifungal antibiotic from an unidentified fungus No. 11243. III. Structure determination
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A novel antifungal antibiotic, FR901469, was isolated from an unidentified fungus No. 11243. It is a water-soluble 40-membered macrocyclic lipopeptidolactone, consisting of D-Ala, L-Tyr, L-Val, trans-4OH-L-Pro, trans-3OH-L-Pro, threo-3OH-L-Gln, Gly, L-Orn, L-Thr, three residues of D-allo Thr and a (3R)-hydroxypalmitic acid. Its structure, including absolute configurations, was unequivocally determined as 1 based on chemical and spectroscopic evidence.
- Fujie,Muramatsu,Yoshimura,Hashimoto,Shigematsu,Takase
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p. 588 - 594
(2007/10/03)
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- Chemoenzymatic Synthesis of cis-4-Hydroxy-D-proline
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Candida antarctica lipase fraction B (CALB) catalyzed the hydrolysis of the (S)-enantiomer of racemic 4-oxo-1,2-pyrrolidinedicarboxylic acid dimethyl ester with high enantioselectivity (> 99.5% ee at 51% conversion). Regioselective hydrogenation of the isolated (R)-4-oxo-1,2-pyrrolidinedicarboxylic acid dimethyl ester produced (2R,4R)-4-hydroxy-1,2-pyrrolidinedicarboxylic acid dimethyl ester in 98% yield, and subsequent hydrolysis of the ester and N-(alkoxycarbonyl) groups produced cis-4-hydroxy-D-proline in 98% yield and 96% de. Diastereomeric mixtures of 4-hydroxy-1,2-pyrrolidinedicarboxylic acid dimethyl esters were also resolved using CALB to produce cis-4-hydroxy-D-proline or trans-4-hydroxy-L-proline in 93 to > 99.5% diastereomeric excess.
- Sigmund, Amy E.,Hong, Wonpyo,Shapiro, Rafael,DiCosimo, Robert
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p. 587 - 590
(2007/10/03)
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- Low molecular weight bicyclic thrombin inhibitors
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This invention relates to the discovery of heterocyclic competitive inhibitors of the enzyme thrombin, their preparation, and pharmaceutical compositions thereof. As well, this invention relates to the use of such compounds and compositions in vitro as anticoagulants and in vivo as agents for the treatment and prophylaxis of thrombotic disorders such as venous thrombosis, pulmonary embolism and arterial thrombosis resulting in acute ischemic events such as myocardial infarction or cerebral infarction. Moreover, these compounds and compositions have therapeutic utility for the prevention and treatment of coagulopathies associated with coronary bypass operations as well as restenotic events following transluminal angioplasty.
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- Substituted quinoxaline-2-ones as glutamate receptor antagonists
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A novel series of substituted quinoxaline 2-ones useful as neuroprotective agents are taught. Novel intermediates, processes of preparation, and pharmaceutical compositions containing the compounds are also taught. The compounds are glutamate receptor antagonists and are useful in the treatment of stroke, cerebral ischemia, or cerebral infarction resulting from thromboembolic or hemorrhagic stroke, cerebral vasospasms, hypoglycemia, cardiac arrest, status epilepticus, perinatal asphyxia, anoxia, seizure disorders, pain, Alzheimer's, Parkinson's, and Huntington's Diseases.
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- Spiro[pyrrolidine-2,3'-oxindole] compounds and methods of use
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The invention provides spiro[pyrrolidine-2,3'-oxindole] compounds produced by the stereo- and regio-selective reaction of variously substituted isatins, alpha -amino acids, and dipolarophiles (e.g., trans-chalcones, acrylate esters, or vinyl oxindoles).
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- Enzymatic production of trans-4-hydroxy-L-proline by regio- and stereospecific hydroxylation of L-proline.
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A proline 4-hydroxylase gene, which was cloned from Dactylosporangium sp. RH1, was overexpressed in Escherichia coli W1485 on a plasmid under a tryptophan tandem promoter after the codon usage of the 5' end of the gene was optimized. The proline 4-hydroxylase activity was l600-fold higher than that in Dactylosporangium sp. RH1. trans-4-Hydroxy-L-proline(Hyp) was produced and accumulated to 41 g/L (87% yield from L-proline) in 100 h when the recombinant E. coli was cultivated in a medium containing L-proline and glucose. 2-Oxoglutarate, which is necessary for the hydroxylation of L-proline by proline 4-hydroxylase, was apparently supplied from glucose through the cellular metabolic pathway. The putA mutant of W1485, which is not able to degrade L-proline, has allowed the quantitative conversion of L-proline to Hyp. The formation of other isomers of hydroxyproline was not observed. Productivity of Hyp was almost the same in a larger-scale culture. The method of manufacturing Hyp from L-proline was established.
- Shibasaki,Mori,Ozaki
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p. 746 - 750
(2007/10/03)
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- Synthesis of DNA-(3')-PNA chimeras with conformationally restricted linkers based on 4-hydroxyproline
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The synthesis and evaluation of DNA-(3')-PNA chimeras containing rigid linkers based on (R/S)-4-hydroxy-D/L-proline are described. It is shown that installment of the trans-L-linker using the tetrabutylammonium salt of (R)- 4-(4,4'-dimethoxytrityloxy)-N-(thymin-l-yl)acetyl-L-proline (2) leads to a DNA-(3')-PNA chimera which hybridizes efficiently with complementary RNA.
- Verheijen, Jeroen C.,Van Roon, Anne-Marie M.,Van Der Laan, Alexander C.,Van Der Marel, Gijsbert A.,Van Boom, Jacques H.
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p. 493 - 508
(2007/10/03)
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- Substrate selectivities of proline hydroxylases
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Substrate selectivities of microbial proline 4-hydroxylase and proline 3-hydroxylases, all of which were purified from recombinant Escherichia coli, were investigated. L-2-Azetidine carboxylate, 3,4-dehydro-L-proline and L- pipecolinic acid were hydroxylated by those enzymes in regio- and stereospecific manner.
- Shibasaki, Takeahi,Sakurai, Wataru,Hasegawa, Atsuhiro,Uosaki, Youichi,Mori, Hideo,Yoshida, Mayumi,Ozaki, Akio
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p. 5227 - 5230
(2007/10/03)
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- Synthesis of (R)- and (S)-3-(tert-butyldimethylsilyloxy)-1-pyrroline N- oxides - Chiral nitrones for synthesis of biologically active pyrrolidine derivative, Geissman-Waiss lactone
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Tungstate-catalyzed oxidation of O-tert-butyldimethylsilyl (O-TBDMS) protected (R)-3-hydroxypyrrolidine ((R)2), derived from trans-4-hydroxy-L- proline, gave O-TBDMS protected (R)-3-hydroxy-1-pyrroline N-oxide ((R)1), which is a new chiral precursor for the synthesis of Geissman-Waiss lactone. The enantiomeric nitrone (S)-1 was also prepared by the oxidation of (S)-2 derived from L-malic acid.
- Murahashi, Shun-Ichi,Ohtake, Hiroaki,Imada, Yasushi
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p. 2765 - 2766
(2007/10/03)
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- Peptides with an insulin-like action
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Peptides with an insulin-like action, of formula I: STR1 in which G is a hydrogen atom, an amino add residue, or a monosubstituted or polysubstituted amino acid; D is an amino acid residue, a phosphoamino acid residue, a monosaccharide residue, or a covalent bond; E is --NH--(CH2)n --NR52, a glycerol residue, or --NH--(CH2)p --R6 --R7 ; R1 is (C1 -C4)-alkyl or =O; R2 is a sulfhydryl protecting group, (C1 -C3)-alkyl, or a hydrogen atom; R3 and R4, independently of one another, are a hydrogen atom or methyl; R5, each being identical or different, is a hydrogen atom, 1 to 6 monosaccharide residues, or 1 to 6 monosubstituted or polysubstituted monosaccharide residues; R6 is O PO4 H, PO2 H, NHCOO, S or OCOO; R7 is a hydrogen atom, 1 to 6 monosaccharide residues, or 1 to 6 monosubstituted or polysubstituted monosaccharide residues; w is an integer 1 or 2; their preparation and use for treatment of diabetes mellitus or insulin-independent diabetes.
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- A Short Stereoselective Synthesis of cis- and trans-4-Hydroxy-L-proline
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A concise three-step synthesis of cis- and trans-4-hydroxy-L-proline on a preparative scale has been carried out using readily available starting materials.
- Mehlfuehrer, Michaela,Berner, Heinz,Thirring, Klaus
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p. 1291 - 1292
(2007/10/02)
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- Synthetic Studies on Antifungal Cyclic Peptides, Echinocandins. Stereoselective Total Synthesis of Echinocandin D via a Novel Peptide Coupling
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Synthetic studies on the novel fungicidal oligopeptides, echinocandins (1b and 1c), are described.The constituent amino acids 5-8 were synthesized in a stereocontrolled manner from the chiral starting materials, 5a, 6a and 7a, respectively.The coupling of these amino acids was characterized by the use of unprotected amino acid as the C-terminal and 2-pyridyl thiol ester as the N-terminal, and the coupling was performed in the presence of 1-(trimethylsilyl)imidazole (TMSIm) or a catalytic amount of tert-amine to give C-terminal free dipeptides, 14 and 16a, respectively, which were converted to the pentapeptide 17a, a common intermediate for the synthesis of 1b and 1c.The synthesis of 1c was achieved by the cyclization of the hexapeptide 24b.
- Kurokawa, Natsuko,Ohfune, Yasufumi
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p. 6195 - 6222
(2007/10/02)
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- Proline 4-hydroxylase: Stereochemical course of the reaction
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The stereochemical course of the hydroxylation of (S)-proline by proline 4-hydroxylase from Streptomyces griseoviridus P8648 has been investigated using (2S, 4S)[4-2H1]-proline and (2S, 4R)-[4-2H1]-proline and found to occur with retention of stereochemistry at C-4 of proline.
- Baldwin, Jack E.,Field, Robert A.,Lawrence, Christopher C.,Merritt, Kirsten D.,Schofield, Christopher J.
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p. 7489 - 7492
(2007/10/02)
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- Intermolecular Stereoselective Alkenylation of Chiral N-Acylpyrrolidinium Ions
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Vinylation of the three cyclic, optically active N-Acylpyrrolidinium ions 5, 8, and 12 with the vinylcopper reagent 2-methyl-1-propenylcopper displays a moderate-to-high trans selectivity with respect to the ring substituents.The absolute configuration of the vinylated products has been confirmed by ozonolysis of the double bond and subsequent degradation to the known amino acids (2S,5S)-pyrrolidine-2,5-dicarboxylic acid, trans-4-hydroxy-L-proline, and trans-3-hydroxy-D-proline.
- Thaning, Mikkel,Wistrand, Lars-G.
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p. 194 - 199
(2007/10/02)
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- Concise Stereoselective Synthesis of (2S,4R)-4-Hydroxyproline from (S)-O-Benzylglycidol by a Novel Cyclization
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An efficient stereoselective route to (2S,4R)-4-hydroxyproline from (S)-O-benzylglycidol has been established via a novel iodine-mediated cyclization of the N-benzoyl-γ,δ-unsaturated amide.
- Takano, Seiichi,Iwabuchi, Yoshiharu,Ogasawara, Kunio
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p. 1527 - 1528
(2007/10/02)
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- Alkylation in the 2-Position of (2S,4R)-4-Hydroxyproline with Retention of Configuration
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O-Acetyl-4-hydroxyproline (1b) is condensed with pivalaldehyde to give a single stereoisomer of the 2-(tert-butyl)-4-oxo-3-oxa-1-azabicyclooct-7-yl acetate (3).This is converted to the enolates 4 or 5, reactions of which with alkyl halides, aldehydes, and acetone (-->6,9,10,11) are diastereoselective (lk-1,3-induction).Cleavage of the corresponding products furnishes the enantiomerically pure 2-deuterio-, 2-methyl-, 2-allyl-, and 2-benzyl-substituted 4-hydroxyprolines 2a-2d.
- Weber, Theodor,Seebach, Dieter
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p. 155 - 161
(2007/10/02)
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- A Short-step Synthesis of 4-Hydroxyproline
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The reaction of N-benzyl-, N-diphenylmethyl-, or N-(1-phenylpropyl)-α-methoxycarbonylmethanimine N-oxide newly prepared with acrylaldehyde in benzene, followed by hydrogenolysis over palladium hydroxide and by acid hydrolysis, gave 4-hydroxyprolines.
- Hara, Junko,Inouye, Yoshinobu,Kakisawa, Hiroshi
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p. 3871 - 3872
(2007/10/02)
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- Alicyclic Nitrosamines and Nitrosamino Acids as Transnitrosating Agents
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Many alicyclic nitrosamines act as nitrosating agents under mild conditions (pH 1-3, in the presence of nucleophilic catalysts such as thiocyanate).All nitrosopiperazines, nitrosomorpholines, and nitrosamino acids tested were found to act as nitrosating agents, and certain nitrosopiperidines also showed this capability.Acyclic nitrosamines are far less reactive than functionally similar cyclic compounds.
- Singer, Sandra S.,Singer, George M.,Cole, Barbara B.
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p. 4931 - 4935
(2007/10/02)
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