scholarly journals Quantitation of erythrocyte pentose pathway flux with [2-13C]glucose and1H NMR analysis of the lactate methyl signal

2004 ◽  
Vol 51 (6) ◽  
pp. 1283-1286 ◽  
Author(s):  
Teresa C. Delgado ◽  
M. Margarida Castro ◽  
Carlos F. Geraldes ◽  
John G. Jones
Keyword(s):  
Nmr Analysis ◽  
Pathway Flux ◽  
Pentose Pathway

Kinetic superiority of intra- vs. extracellular pentose pathway flux: studies in porous adipocytes

1991 ◽  
Vol 261 (3) ◽  
pp. C476-C481 ◽  
Author(s):  
K. L. McCormick ◽  
G. J. Mick
Keyword(s):  
Steady State ◽  
Reference System ◽  
Enzyme System ◽  
Cell Disruption ◽  
Intermediary Metabolism ◽  
Rat Adipocytes ◽  
Cellular Effects ◽  
Solubilized Enzyme ◽  
Pathway Flux ◽  
Pentose Pathway

Considering how the cytosol is typically prepared, to wit, by cell disruption and ultracentrifugation, historically this compartment has been deemed unstructured and kinetically analogous to a solubilized system. By prudently permeabilizing rat adipocytes so that there is scant enzyme egress, intermediary metabolism can be explored intracellularly. Herein, cytoplasmic flux vs. a soluble reference system was compared. The three-enzyme oxidative portion of the pentose pathway was examined using [1-14C]glucose 6-phosphate (G-6-P); both the steady-state velocities (nu o) and transient times (tau ss) were compared in each system. At low G-6-P levels (much less than km), nu o is dependent solely on the activity of the first enzyme, and tau ss is determined by the distal two enzymes. In our experiments, the need also arose to compare tau ss between preparations, wherein the enzyme concentrations were unequal. It is shown that tau ss.nu o/G-6-P serves as an index of kinetic efficiency. Over various dilutions, the kinetic value (nu o/G-6-P) for the porous cells ranged from 2.0 to 23.9 x 10(-6) l/min, with corresponding tau ss values of 18-1.0 min. The respective values for the solubilized enzyme system were from 4.9 to 42.2 x 10(-6) l/min and from 15.2 to 1.1 min. This abbreviated pathway occurring in porous cells was nearly twice as fast at reaching steady state than the corresponding solubilized system. We conclude that cytoplasmic flux is kinetically efficient and that metabolic studies conducted only under Vmax conditions and ignoring tau ss could overlook the cellular effects of hormones or pathological states.

Synthesis and Structure Assignment of 2-(4-Methoxybenzyl)cyclohexyl β-D-Glucopyranoside Enantiomers

2006 ◽  
Vol 71 (10) ◽  
pp. 1470-1483 ◽  
Author(s):  
David Šaman ◽  
Pavel Kratina ◽  
Jitka Moravcová ◽  
Martina Wimmerová ◽  
Zdeněk Wimmer
Keyword(s):  
Analytical Data ◽  
Chiral Hplc ◽  
Nmr Analysis ◽  
Target Structure ◽  
Enantiomerically Pure ◽  
Whole Cells ◽  
H Nmr ◽  
Structure Assignment ◽  
Related Compounds ◽  
C Nmr

Glucosylation of the cis- and trans-isomers of 2-(4-methoxybenzyl)cyclohexan-1-ol (1a/1b, 2a/2b, 1a or 2a) was performed to prepare the corresponding alkyl β-D-glucopyranosides, mainly to get analytical data of pure enantiomers of the glucosides (3a-6b), required for subsequent investigations of related compounds with biological activity. One of the employed modifications of the Koenigs-Knorr synthesis resulted in achieving 85-95% yields of pure β-anomers 3a/3b, 4a/4b, 3a or 4a of protected intermediates, with several promoters and toluene as solvent, yielding finally the deprotected products 5a/5b, 6a/6b, 5a or 6a as pure β-anomers. To obtain enantiomerically pure β-anomers of the target structure (3a, 4a, 5a and 6a) for unambiguous structure assignment, an enzymic reduction of 2-(4-methoxybenzyl)cyclohexan-1-one by Saccharomyces cerevisiae whole cells was performed to get (1S,2S)- and (1S,2R)-enantiomers (1a and 2a) of 2-(4-methoxybenzyl)cyclohexan-1-ol. The opposite enantiomers of alkyl β-D-glucopyranosides (5b and 6b) were obtained by separation of the diastereoisomeric mixtures 5a/5b and 6a/6b by chiral HPLC. All stereoisomers of the products (3a-6b) were subjected to a detailed 1H NMR and 13C NMR analysis.

scholarly journals Structural Characterization of a Polysaccharide from Gastrodia elata and Its Bioactivity on Gut Microbiota

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4443
Author(s):  
Jiangyan Huo ◽  
Min Lei ◽  
Feifei Li ◽  
Jinjun Hou ◽  
Zijia Zhang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Citric Acid ◽  
Gut Microbiota ◽  
Structural Characterization ◽  
Hot Water ◽  
Nmr Analysis ◽  
Gastrodia Elata ◽  
Hot Water Extraction ◽  
Hydroxybenzyl Alcohol

A novel homogeneous polysaccharide named GEP-1 was isolated and purified from Gastrodia elata (G. elata) by hot-water extraction, ethanol precipitation, and membrane separator. GEP-1, which has a molecular weight of 20.1 kDa, contains a polysaccharide framework comprised of only glucose. Methylation and NMR analysis showed that GEP-1 contained 1,3,6-linked-α-Glcp, 1,4-linked-α-Glcp, 1,4-linked-β-Glcp and 1,4,6-linked-α-Glcp. Interestingly, GEP-1 contained citric acid and repeating p-hydroxybenzyl alcohol as one branch. Furthermore, a bioactivity test showed that GEP-1 could significantly promote the growth of Akkermansia muciniphila (A. muciniphila) and Lacticaseibacillus paracasei (L.paracasei) strains. These results implied that GEP-1 might be useful for human by modulating gut microbiota.

scholarly journals Mono- and Dinitro-BN-Naphthalenes: Formation and Characterization

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4209
Author(s):  
Mao-Xi Zhang ◽  
Nathaniel B. Zuckerman ◽  
Philip F. Pagoria ◽  
Bradley A. Steele ◽  
I-Feng Kuo ◽  
...  
Keyword(s):  
Electron Density ◽  
Nmr Analysis ◽  
X Ray ◽  
Boron Nitrogen

Mono- and dinitro-BN-naphthalenes, i.e., 1-nitro-, 3-nitro-, 1,6-dinitro-, 3,6-dinitro-, and 1,8-dinitro-BNN, were generated in the nitration of 9,10-BN-naphthalene (BNN), a boron–nitrogen (BN) bond-embedded naphthalene, with AcONO2 and NO2BF4 in acetonitrile. The nitrated products were isolated and characterized by NMR, GC-MS, IR, and X-ray single crystallography. The effects of the nitration on the electron density and aromaticity of BNN were evaluated by B-11 NMR analysis and HOMA calculations.

scholarly journals NMR lipid profiles of cells, tissues, and body fluids: proton NMR analysis of human erythrocyte lipids.

1994 ◽  
Vol 35 (11) ◽  
pp. 1925-1931
Author(s):  
R K Adosraku ◽  
G T Choi ◽  
V Constantinou-Kokotos ◽  
M M Anderson ◽  
W A Gibbons
Keyword(s):  
Human Erythrocyte ◽  
Proton Nmr ◽  
Body Fluids ◽  
Lipid Profiles ◽  
Nmr Analysis ◽  
Erythrocyte Lipids
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