124489-20-9Relevant articles and documents
Mass Spectrometric Characterization of Human Serum Albumin Adducts Formed with N-Oxidized Metabolites of 2-Amino-1-methylphenylimidazo[4,5- b ]pyridine in Human Plasma and Hepatocytes
Wang, Yi,Peng, Lijuan,Bellamri, Medjda,Langou?t, Sophie,Turesky, Robert J.
, p. 1045 - 1059 (2015)
2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), a carcinogenic heterocyclic aromatic amine formed in cooked meats, is metabolically activated to electrophilic intermediates that form covalent adducts with DNA and protein. We previously identified
Heterogeneous DNA Adduct Formation in Vitro by the Acetylated Food Mutagen 2-(Acetoxyamino)-1-methyl-6-phenylimidazo[4,5-b]pyridine: A Fluorescence Spectroscopic Study
Marsch, Glenn A.,Goldman, Eli N.,Fultz, Esther,Shen, Nancy H.,Turteltaub, Kenneth W.
, p. 659 - 670 (1995)
The food mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) forms adducts to DNA guanine bases at the C-8 position. No other DNA adduction site has been verified for PhIP, nor has any experimental data been collected on the conformation of the PhIP-DNA covalent complex. To determine if multiple PhIP-DNA adduct species exist, or if PhIP-DNA adducts assume multiple conformations, 2-(acetoxyamino)-1-methyl-6-phenylimidazo[4,5-b]pyridine (N-acetoxy-PhIP) was reacted with calf thymus DNA, followed by an evaluation of the resulting adduct complexes by fluorescence spectroscopy. Approximately 20 percent of the N-acetoxy-PhIP formed covalent complexes with DNA. Two major and several minor spots were observed by 32P-postlabeling, suggesting a minimum of two major adduct species. UV/vis spectra of the PhIP-modified DNA also showed heterogeneous formation of PhIP-DNA adducts. Fluoroscence excitation and emission spectroscopy with or without fluorescence quenching (silver ion and acrylamide) was used to evaluate the number of adducts formed, and the low-resulation conformation of each adduct. Four adduct fluorophores were observed and assigned the nomenclature PAi, where "PA" denotes PhIP Adduct and i = 1-4 in order of fluorescence emission band energies, with 1 the highest and 4 the lowest energy, respectively. Excitation maxima for the adduct fluorophores ranged from 340 to 370 nm, and emission maxima ranged from 390 to 420 nm. The fluorescence from adduct PA1 was quenched by silver but not acrylamide, suggesting a helix-internal configuration. Adduct PA2 fluorescence was strongly enhanced upon silver binding but was not affected by acrylamide, also indicating that this adduct was internal. The fluoroscence from adducts PA3 and PA4 was quenched by acrylamide but not silver; thus PA2 and PA3 were tentatively assigned as solvent-accessible. These data are the first suggesting heterogeneous formation of PhIP adducts to intact DNA, but we cannot as yet determine how many chemical species of adduct are formed or if a given species exists in multiple conformations.
Capturing labile sulfenamide and sulfinamide serum albumin adducts of carcinogenic arylamines by chemical oxidation
Peng, Lijuan,Turesky, Robert J.
, p. 1065 - 1072 (2013/03/14)
Aromatic amines and heterocyclic aromatic amines (HAAs) are a class of structurally related carcinogens that are formed during the combustion of tobacco or during the high temperature cooking of meats. These procarcinogens undergo metabolic activation by
Mapping serum albumin adducts of the food-borne carcinogen 2-amino-1-methyl-6-phenylimidazo[4,5- b ]pyridine by data-dependent tandem mass spectrometry
Peng, Lijuan,Dasari, Surendra,Tabb, David L.,Turesky, Robert J.
, p. 2179 - 2193 (2013/01/15)
2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is a heterocyclic aromatic amine that is formed during the cooking of meats. PhIP is a potential human carcinogen: it undergoes metabolic activation to form electrophilic metabolites that bind to DNA
Synthesis and decomposition of an ester derivative of the procarcinogen and promutagen, PhIP, 2-amino-1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridine: Unusual nitrenium ion chemistry
Nguyen, Thach-Mien,Novak, Michael
, p. 4698 - 4706 (2008/02/10)
(Chemical Equation Presented) The food-derived heterocyclic amine (HCA) carcinogen 2-amino-1-methyl-6-phenyl-1H-imidazo[4,5-b]-pyridine, PhIP, is often generated in the highest concentration of the HCAs formed during broiling and frying of meat and fish. Although it is considered to be an important contributor to human cancer risk from exposure to HCAs, the chemistry of PhIP metabolites that presumably react with DNA to initiate carcinogenesis has received only cursory attention. We have synthesized the ester derivative N-pivaloxy-2-amino-1-methyl-6-phenyl-1H-imidazo[4,5-b]pyridine, 1b, and investigated its chemistry in aqueous solution. Although 1b was too unstable to isolate, we could characterize it by NMR methods in DMF-d7, a solvent in which it is stable at -40°C. It decomposed rapidly in aqueous solution, but its conjugate acid, 1bH+, is not reactive. The nitrenium ion, 2, was trapped by N3- to form the unusual tetrazole adduct, 16. In the absence of N3-, the expected hydration products of 2 were not detected, but the reduction product, 12, was detected. Although such products are often taken as evidence of triplet nitrenium ions, the efficient trapping of 2 by N3- indicates that it is a ground state singlet species. The product 12 appears to be generated by reduction of an initially formed hydration product of 2. An alternative addition-elimination mechanism for the formation of 12 does not fit the available kinetic data. The selectivity of 2, measured as kaz/k s, the ratio of the second-order rate constant for its reaction with N3- and the first-order rate constant for its reaction with the aqueous solvent, is (2.3 ± 0.6) × 104 M -1, a value that is in the middle of the range of k az/ks of 10-106 M-1 observed for nitrenium ions derived from other HCAs. The mutagenicity of aromatic amines (AAs) and HCAs, measured as the log of histidine revertants per nanomole of amine, log m, in Salmonella typhimurium TA 98 and TA 100 correlates with log(kaz/ks) for a wide variety of carbocyclic and heterocyclic amine mutagens including PhIP. Previously developed linear regression models for mutagenicity that include log(kaz/k s) as an independent variable predict log m for PhIP with good accuracy in both TA 98 and TA 100. Quantitative carcinogenicity data are less strongly correlated with log(kaz/ks), so prediction of the carcinogenicity of PhIP and other HCAs or AAs based primarily on log(k az/ks) is less successful.