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Keto Acid (keto + acid)

Distribution by Scientific Domains
Chemistry93%

Selected Abstracts

ChemInform Abstract: 5-Oxocyclooctanecarboxylic Acid: Hydrogen-Bonding Pattern and Conformational Disorder in a Medium-Ring ,-Keto Acid.

CHEMINFORM, Issue 6 2001
Roger A. Lalancette
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

Synthesis of Chiral 5-Aryltetrahydrofuran-2-ones via Yeast Bioreduction of ,-Keto Acids and Their Esters.

CHEMINFORM, Issue 41 2006
N. O. Mahmoodi
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Synthesis of ,-Ketobutyrolactones and ,-Hydroxy-,-Keto Acids.

CHEMINFORM, Issue 18 2004
Han-Young Kang
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

A Simple Synthesis of ,-Methyl-,-keto Acids.

CHEMINFORM, Issue 9 2007
B. V. Pawar
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

Pyruvate reduces DNA damage during hypoxia and after reoxygenation in hepatocellular carcinoma cells

FEBS JOURNAL, Issue 19 2007
Emilie Roudier
Pyruvate is located at a crucial crossroad of cellular metabolism between the aerobic and anaerobic pathways. Modulation of the fate of pyruvate, in one direction or another, can be important for adaptative response to hypoxia followed by reoxygenation. This could alter functioning of the antioxidant system and have protective effects against DNA damage induced by such stress. Transient hypoxia and alterations of pyruvate metabolism are observed in tumors. This could be advantageous for cancer cells in such stressful conditions. However, the effect of pyruvate in tumor cells is poorly documented during hypoxia/reoxygenation. In this study, we showed that cells had a greater need for pyruvate during hypoxia. Pyruvate decreased the number of DNA breaks, and might favor DNA repair. We demonstrated that pyruvate was a precursor for the biosynthesis of glutathione through oxidative metabolism in HepG2 cells. Therefore, glutathione decreased during hypoxia, but was restored after reoxygenation. Pyruvate had beneficial effects on glutathione depletion and DNA breaks induced after reoxygenation. Our results provide more evidence that the ,-keto acid promotes the adaptive response to hypoxia followed by reoxygenation. Pyruvate might thus help to protect cancer cells under such stressful conditions, which might be harmful for patients with tumors. [source]

(±)-3-Oxocyclo­pentanecarboxylic acid: the smallest keto acid known to aggregate by catemeric hydrogen bonding

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2006
Muhammad H. Malak
The title compound, C6H8O3, is the smallest keto acid yet found to aggregate in the solid as acid-to-ketone hydrogen-bonded catemers. Four translational chains pass through the cell in the a direction [O,O = 2.6915,(14),Å and O,H,O = 166°]. Two inter­molecular C,H,O close contacts exist, involving both carbonyl functions. [source]

4-Oxo­cyclo­hexane­carboxyl­ic acid: hydrogen bonding in the monohydrate of a ,-keto acid

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 2 2004
Alan Barcon
The title monohydrate, C7H10O3·H2O, aggregates as a complex hydrogen-bonding network, in which the water mol­ecule accepts a hydrogen bond from the carboxyl group of one mol­ecule and donates hydrogen bonds to ketone and carboxyl Czdbnd;O functions in two additional mol­ecules, yielding a sheet-like structure of parallel ribbons. The keto acid adopts a chiral conformation through rotation of the carboxyl group by 62.50,(15)° relative to the plane defined by its point of attachment and the ketone C and O atoms. Two C,H,O close contacts exist in the structure. [source]

(±)-(2,3,4,4a,5,6,7,8-Octa­hydro-2-oxo­naphthalen-1-yl)acetic acid: hydrogen-bonding pattern of the mono­hydrate of an unsaturated bicyclic ,-keto acid

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 8 2002
Roger A. Lalancette
In the title compound, C12H16O3·H2O, the water of hydration accepts a hydrogen bond from the carboxyl group and donates hydrogen bonds to the carboxyl carbonyl and the ketone groups of two different neighbors, yielding a complex three-dimensional hydrogen-bonding array. There are two independent hydrated mol­ecules in the asymmetric unit (Z, = 2) related by a pseudo-translation. [source]

Synthesis of the ,-keto acids from benzimidazolium iodides and ethyl malonate

CHINESE JOURNAL OF CHEMISTRY, Issue 6 2000
Zhen Shi
Abstract The reaction of benzimidazole methiodide with ethyl malonate in the existence of base was studied, and a new convenient synthetic method of the ,-keto acid was provided. [source]

Methionine gamma-lyase: The unique reaction mechanism, physiological roles, and therapeutic applications against infectious diseases and cancers

IUBMB LIFE, Issue 11 2009
Dan Sato
Abstract Sulfur-containing amino acids (SAAs) are essential components in many biological processes and ubiquitously distributed to all organisms. Both biosynthetic and catabolic pathways of SAAs are heterogeneous among organisms and between developmental stages, and regulated by the environmental changes. Limited lineage of organisms ranging from archaea to plants, but not human, possess a unique enzyme methionine gamma-lyase (MGL, EC 4.4.1.11) to directly degrade SAA to ,-keto acids, ammonia, and volatile thiols. The reaction mechanisms and the physiological roles of this enzyme are partially demonstrated by the enzymological analyzes, structure determination, isotopic labeling of the intermediate metabolites, and functional analyzes of deficient mutants. MGL has been exploited as a drug target for the infectious diseases caused by parasitic protozoa and anaerobic periodontal bacteria. In addition, MGL has been utilized to develop therapeutic interventions of various cancers, by introducing recombinant proteins to deplete methionine essential for the growth of cancer cells. In this review, we discuss the current understanding of enzymological properties, putative physiological roles, and therapeutic applications of MGL. © 2009 IUBMB IUBMB Life, 61(11): 1019,1028, 2009 [source]

Thermal deactivation and inhibition of D -Amino acid oxidase in permeabilized cells of the yeast Trigonopsis variabilis

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 4 2004
José A Moreno
Abstract The inhibition of D -amino acid oxidase contained in permeabilized cells of the yeast Trigonopsis variabilis by ,-keto acids (pyruvic acid, phenylpyruvic acid and 4-methylthio-2-oxobutanoic acid), products of the transformation of the corresponding D -amino acids, was studied. In all cases, inhibition was of the mixed type and significant differences with respect to the inhibition shown by the enzyme from other sources such as pig kidney or the yeast Rhodotorula gracilis were observed. A study was also made of the thermal deactivation of the enzyme contained in permeabilized cells of T variabilis in the temperature range 30,50 °C in sodium phosphate and Tris hydroxylmethyl aminomethane + CaCl2 buffers. A deactivation mechanism with two steps in series is proposed to account for the variation in activity with time. The results suggest that the enzyme shows greater stability in phosphate buffer, with half-lives between 7.6 days at 30 °C and 8.6 h at 50 °C. Copyright © 2004 Society of Chemical Industry [source]

Stereoselective synthesis of L-[15N] amino acids with glucose dehydrogenase and galactose mutarotase as NADH regenerating system

JOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 4 2008
Maria Chiriac
Abstract We have developed an efficient stereospecific enzymatic synthesis of L-[15N]-valine, L-[15N]-leucine, L-[15N]-norvaline, L-[15N]-norleucine and L-[15N]-isoleucine from the corresponding ,-keto acids by coupling the reactions catalysed by leucine dehydrogenase and glucose dehydrogenase/galactose mutarotase. Giving high yields of L-amino acids, the procedure is economical and easy to perform and to monitor at a synthetically useful scale (1,10,g). Copyright © 2008 John Wiley & Sons, Ltd. [source]

Synthesis of the ,-keto acids from benzimidazolium iodides and ethyl malonate

CHINESE JOURNAL OF CHEMISTRY, Issue 6 2000
Zhen Shi
Abstract The reaction of benzimidazole methiodide with ethyl malonate in the existence of base was studied, and a new convenient synthetic method of the ,-keto acid was provided. [source]

Asymmetric catalysis by chiral lanthanide complexes in water

CHIRALITY, Issue 7 2005
Rachel S. Dickins
Abstract The development of catalytic, asymmetric transformations in water is a challenging task. The lanthanides are becoming reagents of choice for many Lewis acid-catalyzed reactions in aqueous media as they are water tolerant. However, enantioselective reactions catalyzed by lanthanides are difficult to achieve in water due to the instability of the reported catalysts. Herein we report the development of stable, well-defined chiral lanthanide complexes and their effectiveness in the asymmetric reduction of ,-keto acids in aqueous solution. This is the first example of asymmetric reduction by a chiral lanthanide complex in water. Although modest ees are obtained (40,50%) the ytterbium complexes offer a unique advantage as they have the ability to monitor, direct from the reaction mixture, the % ee for the reaction, by 1H NMR, through a dipolar analysis of the observed paramagnetic shift. Chirality 17:357,363, 2005. © 2005 Wiley-Liss, Inc. [source]