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Joon-Kwan Moon et al.
Journal of agricultural and food chemistry, 59(2), 615-618 (2010-12-29)
4(5)-Methylimidazole has received the attention of federal and state regulatory agencies because of its carcinogenicity and common presence in foods and beverages. In the present study, the formation of 4(5)-methylimidazole in Maillard reaction model systems consisting of D-glucose/NH(3), L-rhamnose/NH(3), methylglyoxal/NH(3)
Cédric Moretton et al.
Journal of agricultural and food chemistry, 59(8), 3544-3550 (2011-03-09)
4-Methylimidazole (4MeI) is a nitrogen compound formed during the manufacture of class III and IV caramel colors. The European Commission has limited its content to 250 ppm. Two methods were compared to perform 4MeI quantification in caramels. The first one
Patrick R Porubsky et al.
The Journal of biological chemistry, 283(48), 33698-33707 (2008-09-27)
Human microsomal cytochrome P-450 2E1 (CYP2E1) monooxygenates > 70 low molecular weight xenobiotic compounds, as well as much larger endogenous fatty acid signaling molecules such as arachidonic acid. In the process, CYP2E1 can generate toxic or carcinogenic compounds, as occurs
Hitomi Yamaguchi et al.
Journal of agricultural and food chemistry, 59(18), 9770-9775 (2011-09-02)
A method for the determination of 4(5)-methylimidazole (4MeI) in naturally brewed soy sauce was developed for the first time using solid-phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). SPE on silica-based reversed-phase cartridges with heptafluorobutyric acid as an ion-pairing
National Toxicology Program technical report series, (535)(535), 1-274 (2007-03-08)
4-Methylimidazole is used in the manufacture of pharmaceuticals, photographic chemicals, dyes and pigments, cleaning and agricultural chemicals, and rubber. It has been identified as a by-product of fermentation in foods and has been detected in mainstream and sidestream tobacco smoke.
L Lojková et al.
Food additives and contaminants, 23(10), 963-973 (2006-09-20)
Two polar analytes, 4(5)-methylimidazole (4-MeI) and 2-acetyl-4(5)-(1,2,3,4)-tetrahydroxybutyl-imidazole (THI), were extracted with supercritical carbon dioxide (CO2) modified with aqueous methanol. The method was applied to a roasted coffee powder with good recovery rates. Method efficiency was compared with that of solid-phase
Arijit Roy et al.
Biopolymers, 82(6), 623-630 (2006-03-25)
We have investigated the possible proton transfer pathways from the surface of the protein to the zinc-bound water molecule in the mutant His-64-Ala of human carbonic anhydrase II. Starting with an input of known crystallographic structures of the mutant, we
Matt Hengel et al.
Journal of agricultural and food chemistry, 61(4), 780-789 (2013-01-09)
Since the National Toxicology Program (NTP) identified 4(5)-methylimidazole [4(5)-MI] as a cancer causing chemical in 2007 and the State of California added it to the Proposition 65 list of compounds as a carcinogen on January 7, 2011, many researchers and
Geemitha Ratnayake et al.
Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment, 32(7), 1075-1082 (2015-05-23)
The purpose of this study was to develop a method to quantify 4(5)-methylimidazole (4-MEI), a suspected carcinogen, in carbonated beverages by simple sample dilution and isotope-dilution reverse-phase LC-MS/MS. Isotope dilution using hexa-deuterated methylimidazole (d6-4-MEI) was used to quantify native 4-MEI
Wei Gu et al.
Chemphyschem : a European journal of chemical physics and physical chemistry, 8(17), 2445-2451 (2007-10-27)
Dynamic protonation equilibria in water of one 4-methylimidazole molecule as well as for pairs and groups consisting of 4-methylimidazole, acetic acid and bridging water molecules are studied using Q-HOP molecular dynamics simulation. We find a qualitatively different protonation behavior of
Young-Teck Kim et al.
Talanta, 78(3), 998-1003 (2009-03-10)
Based on the principle of liquid core waveguide, a novel microfluidic device with micro-scale detection window capable of sensing flashlight emitted from rapid 1,1'-oxalyldi-4-methylimidazole (OD4MI) chemiluminescence (CL) reaction was fabricated. Light emitted from OD4MI CL reaction occurring in the micro-dimensional
Kathryn E Muratore et al.
Biochemistry, 48(15), 3378-3386 (2009-03-06)
Protein tyrosine kinases are critical cell signaling enzymes. These enzymes have a highly conserved Arg residue in their catalytic loop which is present two residues or four residues downstream from an absolutely conserved Asp catalytic base. Prior studies on protein
S Casal et al.
Journal of chromatography. A, 976(1-2), 285-291 (2002-12-05)
A GC-MS method is described for quantification of 4-(5-)methylimidazole (4MI) in coffee. Although tested, GC-flame ionization detection proved inadequate for this purpose due to the complexity of the coffee matrix. The developed method was based on ion-pair extraction with bis-2-ethylhexylphosphate
Sabine Gerbal-Chaloin et al.
Molecular pharmacology, 86(6), 624-634 (2014-09-18)
The wingless-type MMTV integration site family (WNT)/β-catenin/adenomatous polyposis coli (CTNNB1/APC) pathway has been identified as a regulator of drug-metabolizing enzymes in the rodent liver. Conversely, little is known about the role of this pathway in drug metabolism regulation in human
F Jay Murray
Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association, 49(1), 320-322 (2010-11-16)
4-Methylimidazole (4-MEI) is found in a wide array of food products. The National Toxicology Program (NTP) recently conducted a two-year feeding cancer bioassay of 4-MEI in B6C3F(1) mice and F344/N rats. In rats, NTP found "equivocal evidence of carcinogenic activity"
P C Chan et al.
Archives of toxicology, 82(1), 45-53 (2007-07-11)
4-Methylimidazole (4MI) is used in the manufacture of pharmaceuticals, photographic chemicals, dyes and pigments, cleaning and agricultural chemicals, and rubber. It has been identified as a by-product of fermentation in foods and has been detected in mainstream and side stream
Jyrki Viidanoja
Journal of chromatography. A, 1480, 106-111 (2016-12-21)
A new liquid chromatography-electrospray ionization-tandem Mass Spectrometry (LC-ESI-MS/MS) method was developed for the determination of more than 20 C1-C6 alkyl and alkanolamines in aqueous matrices. The method employs Hydrophilic Interaction Liquid Chromatography Multiple Reaction Monitoring (HILIC-MRM) with a ZIC-pHILIC column
Po Chan et al.
Archives of toxicology, 80(3), 169-180 (2005-09-24)
Fifteen-day and 14-week studies of 2-methylimidazole (2MI) and 4-methylimidazole (4MI) were conducted because of widespread human exposure via ingestion of food products containing the compounds and lack of toxicity data. Groups of five male and five female Fischer rats and
Kwang-Geun Lee et al.
Food chemistry, 136(3-4), 1165-1168 (2012-12-01)
Aqueous caramel model systems consisted the D-glucose/NH(3)/sulphite were heated at 100°C for 2 h and amounts of carcinogenic 4(5)-methylimidazole (4-MI) formed were determined. The amount formed ranged from 7.0 to 155.0 ppm. A system with 0.1 M sulphite yielded the
Julie Kim et al.
Talanta, 129, 106-112 (2014-08-17)
Using the role of p-iodophenol in enzyme assay, enhanced 1,1'-oxalyldiimidazole chemiluminescent enzyme immunoassays (ODI-CLEIAs) were developed to consecutively quantify trace levels of triple tumor markers, such as alpha fetoprotein (AFP), carcinoembryonic antigen (CEA), and prostate specific antigen (PSA) in a
Eric D Watt et al.
Biophysical journal, 101(2), 411-420 (2011-07-20)
Rate-limiting millisecond motions in wild-type (WT) Ribonuclease A (RNase A) are modulated by histidine 48. Here, we incorporate an unnatural amino acid, thia-methylimidazole, at this site (H48C-4MI) to investigate the effects of a single residue on protein motions over multiple
Shinji Hashimoto et al.
Biochemistry, 45(32), 9660-9667 (2006-08-09)
Ultraviolet resonance Raman (UVRR) spectroscopy has been used to characterize the structure and hydrogen bonding state of the distal histidine (His42) in horseradish peroxidase (HRP) complexed with carbon monoxide (HRP-CO). The HRP-CO - HRP UVRR difference spectrum in D(2)O solution
Linheng Wei et al.
Acta crystallographica. Section C, Crystal structure communications, 65(Pt 9), o453-o456 (2009-09-04)
Cocrystallization of imidazole or 4-methylimidazole with 2,2'-dithiodibenzoic acid from methanol solution yields the title 2:1 and 1:1 organic salts, 2C(3)H(5)N(2)(+).C(14)H(10)O(4)S(2)(2-), (I), and C(4)H(7)N(2)(+).C(14)H(10)O(4)S(2)(-), (II), respectively. Compound (I) crystallizes in the monoclinic C2/c space group with the mid-point of the S-S
Satoshi Ueda et al.
Journal of the American Chemical Society, 134(1), 700-706 (2011-12-01)
The completely N(1)-selective Pd-catalyzed arylation of unsymmetric imidazoles with aryl halides and triflates is described. This study showed that imidazoles have a strong inhibitory effect on the in situ formation of the catalytically active Pd(0)-ligand complex. The efficacy of the
Ileana Elder et al.
Archives of biochemistry and biophysics, 437(1), 106-114 (2005-04-12)
In the site-specific mutant of human carbonic anhydrase in which the proton shuttle His64 is replaced with alanine, H64A HCA II, catalysis can be activated in a saturable manner by the proton donor 4-methylimidazole (4-MI). From 1H NMR relaxivities, we
Borivoj Klejdus et al.
Journal of separation science, 29(3), 378-384 (2006-03-21)
A method for the simultaneous determination of 4(5)-methylimidazole (4MeI) and 2-acetyl-4(5)-(1,2,3,4-tetrahydroxybutyl)-imidazole (THI) was developed using SPE and HPLC/MS. Solid-phase extraction using SCX Disc cartridges was used for isolation of the analytes from liquid samples. The lower LOQwas 0.1 ng/mL for
S Javadian et al.
Journal of molecular graphics & modelling, 27(5), 620-627 (2008-12-03)
A computational investigation was carried out to characterize the (14)N and (2)H electric field gradient, EFG, in four protonated forms of 4-methyl imidazole (4-MeIm) and Histidine. In an attempt to establish metal binding effect in biological systems, we have considered
Jinyuan Wang et al.
Journal of agricultural and food chemistry, 60(4), 917-921 (2012-01-10)
An ultrahigh-performance liquid chromatography (UHPLC) tandem mass spectrometric (MS/MS) method was developed for the simultaneous quantification of 2-acetyl-4-tetrahydroxybutylimidazole (THI), 2- and 4-methylimidazoles (2-MI and 4-MI), and 5-hydroxymethylfurfural (HMF) in beverage samples. A C30 reversed-phase column was used in this method
Tore Sivertsen et al.
Toxicology mechanisms and methods, 19(3), 214-218 (2009-09-05)
4-methylimidazole (4MeI) is a tremorogenic and convulsive agent of concern both in human and veterinary toxicology. The in vitro effects of 4MeI (5 microM-20 mM) on cerebral glutamate decarboxylase (GAD) activity and (in concentrations up to 50 mM) on binding
Holger M Becker et al.
Proceedings of the National Academy of Sciences of the United States of America, 108(7), 3071-3076 (2011-02-02)
Carbonic anhydrases (CAs) catalyze the reversible hydration of CO(2) to HCO(3)(-) and H(+). The rate-limiting step in this reaction is the shuttle of protons between the catalytic center of the enzyme and the bulk solution. In carbonic anhydrase II (CAII)
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