PubMed Health⌕ Search

Biomedical subjects

K Pongracz

Publications and source records attributed to K Pongracz.

At least 19 recordsLinked to original sources
PubMed2001

Telomerase can inhibit the recombination-based pathway of telomere maintenance in human cells.

Telomere length can be maintained by telomerase or by a recombination-based pathway. Because individual telomeres in cells using the recombination-based pathway of telomere maintenance appear to periodically become extremely short, cells using this pathway to maintain telomeres may be faced with a continuous state of crisis. We expressed telomerase in a human cell line that uses the recombination-based pathway of telomere maintenance to test whether telomerase would prevent telomeres from becoming critically short and examine the effects that this might have on the recombination-based pathway of telomere maintenance. In these cells, telomerase maintains the length of the shortest telomeres. In some cases, the long heterogeneous telomeres are completely lost, and the cells now permanently contain short telomeres after only 40 population doublings. This corresponds to a telomere reduction rate of 500 base pairs/population doubling, a rate that is much faster than expected for normal telomere shortening but is consistent with the rapid telomere deletion events observed in cells using the recombination-based pathway of telomere maintenance (Murnane, J. P., Sabatier, L., Marder, B. A., and Morgan, W. F. (1994) EMBO J. 13, 4953-4962). We also observed reductions in the fraction of cells containing alternative lengthening of telomere-associated promyelocytic leukemia bodies and extrachromosomal telomere repeats; however, no alterations in the rate of sister chromatid exchange were observed. Our results demonstrate that human cells using the recombination-based pathway of telomere maintenance retain factors required for telomerase to maintain telomeres and that once the telomerase-based pathway of telomere length regulation is engaged, recombination-based elongation of telomeres can be functionally inhibited.

Chromosome Aberrations↗
PubMed1998

alpha-Oligodeoxyribonucleotide N3'-->P5' phosphoramidates: synthesis and duplex formation.

The synthesis and hybridization properties of novel nucleic acid analogs, alpha-anomeric oligodeoxyribonucleotide N3'-->P5' phosphoramidates, are described. The alpha-3'-aminonucleoside building blocks used for oligonucleotide synthesis were synthesized from 3'-azido-3'-deoxythymidine or 3'-azido-2',3'-dideoxyuridine via acid catalyzed anomerization or transglycosylation reactions. The base-protected alpha-5'-O-DMT-3'-aminonucleosides were assembled into dimers and oligonucleotides on a solid support using the oxidative phosphorylation method.1H NMR analysis of the alpha-N3'-->P5' phosphoramidate dimer structures indicates significant differences in the sugar puckering of these compounds relative to the beta-N3'-->P5' phosphoramidates and to the alpha-phosphodiester counterparts. Additionally, the ability of the alpha-oligonucleotide N3'-->P5' phosphoramidates to form duplexes was studied using thermal denaturation experiments. Thus the N3'-->P5' phosphoramidate decamer containing only alpha-thymidine residues did not bind to poly(A) and exhibited lower duplex thermal stability with poly(dA) than that for the corresponding beta-anomeric phosphoramidate counterpart. A mixed base decamer alpha-CTTCTTCCTT formed duplexes with the RNA and DNA complementary strands only in a parallel orientation. Melting temperatures of these complexes were significantly lower, by 34-47 or 15-25 degrees C, than for the duplexes formed by the isosequential beta-phosphoramidates in antiparallel and parallel orientations respectively. In contrast, the alpha-decaadenylic N3'-->P5' phosphoramidate formed duplexes with both RNA and DNA complementary strands with a stability similar to that of the corresponding beta-anomeric phosphoramidate. Moreover, the self-complementary oligonucleotide alpha-ATATATATAT did not form an alpha:alpha homoduplex. These results demonstrate the effects of 3'-aminonucleoside anomeric configuration on sugar puckering and consequently on stability of the duplexes.

Base Sequence↗
PubMed1998

Oxidation of eugenol to form DNA adducts and 8-hydroxy-2'-deoxyguanosine: role of quinone methide derivative in DNA adduct formation.

We have investigated the activation of eugenol to form DNA adducts and oxidative base damage. Treatment of myeloperoxidase containing HL-60 cells with eugenol, produced a dose-dependent formation of three DNA adducts as detected with P1-enhanced 32P-post-labeling. Incubation of HL-60 cells with the combination of 100 microM eugenol and 100 microM H2O2 potentiated the levels of DNA adduct in HL-60 cells by 14-fold, which suggests peroxidase activation in adduct formation. In vitro activation of eugenol with either horseradish peroxidase or myeloperoxidase and H2O2 produced three DNA adducts that were inhibited by the addition of either ascorbic acid or glutathione, by 66 and 90%, respectively. The DNA adducts formed in HL-60 cells treated with eugenol were the same as those formed by in vitro peroxidase activation. In addition to adduct formation, peroxidase activation of eugenol produced a 2- to 3-fold increase in the level of oxidative base damage. Eugenol quinone methide was prepared by Ag(I)oxide oxidation of eugenol. Peroxidase activation of eugenol gave a product that had the same UV spectrum as eugenol quinone methide, which suggests that it was one of the products. Reaction of eugenol quinone methide with either DNA or deoxyguanosine-3'-phosphate produced two principal adducts (2 and 4). When DNA adduct 2 formed by incubation of eugenol quinone methide with deoxyguanosine-3'-phosphate was compared with DNA 2 adduct formed in HL-60 cells treated with eugenol results demonstrated that they were the same. This suggests that eugenol quinone methide is one of the reactive intermediates leading to DNA adduct formation in cells. Activation of eugenol with 10 microM copper sulfate resulted in the production of one principal (2) and several minor adducts. DNA adduct 2 formed by activation of eugenol with copper sulfate was the same as DNA adduct 2 formed by either peroxidase activation of eugenol or by reactions with eugenol quinone methide, which indicates that the reactive intermediates generated by these activation systems were similar. Copper sulfate produced a 95-fold increase in the level of oxidative base damage, which was significantly inhibited by the addition of either bathocuproinedisulphonic acid or catalase. The formation of oxidative base damage was consistent with a Fenton reaction mechanism. Our results demonstrate that eugenol can be activated to form both DNA adducts and oxidative base damage. We propose that the formation of this DNA damage may contribute to the observed toxic properties of eugenol.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1996

Activation of 4-hydroxytamoxifen and the tamoxifen derivative metabolite E by uterine peroxidase to form DNA adducts: comparison with DNA adducts formed in the uterus of Sprague-Dawley rats treated with tamoxifen.

Daily intraperitoneal treatment of female Sprague-Dawley rats with either 5, 10 or 20 mg/kg tamoxifen (TAM) for 1 week increased the level of peroxidase activity in the uterus 2- to 10-fold compared to the control level. Using uterine extracts prepared from control and TAM treated animals, we investigated the activation of 4-hydroxytamoxifen (4-HO-TAM) and (E,Z)-1,2-diphenyl-1-(4-hydroxyphenyl)-but-1-ene (cis/trans-metabolite E) to form DNA adducts. Activation of 4-HO-TAM by uterine extracts prepared from either control or TAM-treated rats produced one major (a) and two minor DNA (b and c) adducts. A similar activation of cis/trans-metabolite E produced two adducts (d and e). There was good correlation between levels of uterine peroxidase activity and levels of DNA adducts formed by 4-HO-TAM and cis/trans-metabolite E. Activation of 4-HO-TAM and cis/trans-metabolite E with horseradish peroxidase (HRP) produced the same adducts as observed by activation with uterine extract. Treatment of Sprague-Dawley rats with 5 and 10 mg/kg for 7 days produced eleven DNA adducts in the liver with no adducts detected in the uterus. However, treatment of rats with 20 mg/kg of TAM for 7 days produced the same adduct pattern in the liver and also one major adduct (1) in the uterus with a relative adduct level of 6.4 - 4.1 x 10(-9). Tamoxifen-DNA adduct 1 detected both in the liver and in the uterus of treated rats was similar to adducts produced by activation of 4-HO-TAM with either uterine extract or HRP. The results of these studies suggest a general model whereby the tamoxifen metabolite 4-HO-TAM is further activated in the uterus by peroxidase enzymes to form DNA adducts.

Alkenes↗
PubMed1996

Investigation of the DNA adducts formed in B6C3F1 mice treated with benzene: implications for molecular dosimetry.

We have investigated the formation of DNA adducts in the bone marrow and white blood cells of male B6C3F1 mice treated with benzene using P1-enhanced 32P-postlabeling. No adducts were detected in the bone marrow of controls or mice treated with various doses of benzene once a day. After twice-daily treatment for 1 to 7 days with benzene, 440 mg/kg, one major (no. 1) and up to two minor DNA adducts were detected in both the bone marrow and white blood cells. The relative adduct levels in these cells ranged from 0.06 to 1.46 x 10(-7). a significant correlation (r2 = 0.95) between levels of adducts in bone marrow and white blood cells was observed. After a 7-day treatment with benzene, 440 mg/kg twice a day, the number of cells per femur decreased from 1.6 x 10(7) to 0.85 x 10(7), indicating myelotoxicity. In contrast, administration of benzene once a day produced only a small decrease in bone marrow cellularity. The observed induction of toxicity in bone marrow was paralleled by formation of DNA adducts. In vitro treatment of bone marrow with hydroquinone (HQ) for 24 hr produced the same DNA adducts as found after treatment of mice with benzene, suggesting that HQ is the principal metabolite of benzene leading to DNA adduct formation in vivo. Using P-postlabeling the principal DNA adduct formed in vivo was compared with N2-(4-hydroxyphenyl)-2'-deoxyguanosine-3'-phosphate. The results of this comparison demonstrated that the DNA adduct formed in vivo co-chromatographs with N2-(4-hydroxyphenyl)-2'-deoxyguanosine-3'-phosphate. These studies indicate that metabolic activation of benzene leads to the formation of DNA adducts in bone marrow and white blood cells and suggest that measurement of DNA adducts in white blood cells may be an indicator of biological effect following benzene exposure.

Animals↗
PubMed1995

Activation of the tamoxifen derivative metabolite E to form DNA adducts: comparison with the adducts formed by microsomal activation of tamoxifen.

(Z)-1,2-Diphenyl-1-(4-hydroxyphenyl)but-1-ene (metabolite E) has been detected in the plasma of patients treated with tamoxifen. We therefore investigated whether the cis/trans isomers of metabolite E can be activated to form DNA adducts detected by 32P postlabeling. Microsomal activation of metabolite E produced two major (a and b) and up to six minor DNA adducts. Activation with horseradish peroxidase or silver(I)oxide produced the same adducts (a and b). Microsomal activation of tamoxifen produced one major (no. 6) and several minor DNA adducts. Rechromatography showed that adducts a and b formed by enzymatic and chemical activation of metabolite E were the same as adducts 9 and 4 produced by microsomal activation of tamoxifen. These results demonstrate that activation of metabolite E can lead to DNA adduct formation.

Alkenes↗
PubMed1995

The benzene metabolite p-benzoquinone forms adducts with DNA bases that are excised by a repair activity from human cells that differs from an ethenoadenine glycosylase.

Benzene is a ubitiquous human environment mental carcinogen. One of the major metabolites is hydroquinone, which is oxidized in vivo to give p-benzoquinone (p-BQ). Both metabolites are toxic to human cells. p-BQ reacts with DNA to form benzetheno adducts with deoxycytidine, deoxyadenosine, and deoxyguanosine. In this study we have synthesized the exocyclic compounds 3-hydroxy-3-N4-benzetheno-2'-deoxycytidine (p-BQ-dCyd) and 9-hydroxy-1,N6-benzetheno-2'-deoxyadenosine (p-BQ-dAdo), respectively, by reacting deoxycytidine and deoxyadenosine with p-BQ. These were converted to the phosphoamidites, which were then used to prepare site-specific oligonucleotides with either the p-BQ-dCyd or p-BQ-dAdo adduct (pbqC or pbqA in sequences) at two different defined positions. These oligonucleotides were efficiently nicked 5' to the adduct by partially purified HeLa cell extracts--the pbqC-containing oligomer more rapidly than the pbqA-containing oligomer. In contrast to the enzyme binding to derivatives produced by the vinyl chloride metabolite chloroacetaldehyde, the oligonucleotides up to 60-mer containing p-BQ adducts did not bind measurably to the same enzyme preparation in a gel retardation assay. Furthermore, there was no competition for the binding observed between oligonucleotides containing 1,N6-etheno A deoxyadenosine (1,N6-etheno-dAdo; epsilon A in sequences) and these oligomers containing either of the p-BQ adducts, even at 120-fold excess. When highly purified fast protein liquid chromatography (FPLC) enzyme fractions were obtained, there appeared to be two closely eluting nicking activities. One of these enzymes bound and cleaved the epsilon A-containing deoxyoligonucleotide. The other enzyme cleaved the pbqA- and pbqC-containing deoxyoligonucleotides. One additional unexpected fact was that bulk p-BQ-treated salmon sperm DNA did compete effectively with the epsilon A-containing oligonucleotide for protein binding. This raises the possibility that such DNA contains other, as-yet-uncharacterized adducts that are recognized by the same enzyme that recognizes the etheno adducts. In summary, we describe a previously undescribed human DNA repair activity, possibly a glycosylase, that excises from DNA pbqC and pbqA, exocyclic adducts resulting from reaction of deoxycytidine and deoxyadenosine with the benzene metabolite, p-BQ. This glycosylase activity is not identical to the one previously reported from this laboratory as excising the four etheno bases from DNA.

Autoradiography↗
PubMed1995

Microsomal and peroxidase activation of 4-hydroxy-tamoxifen to form DNA adducts: comparison with DNA adducts formed in Sprague-Dawley rats treated with tamoxifen.

Using rat liver microsomal preparations and peroxidase enzymes, we have investigated the formation of DNA adducts by the antiestrogen compound tamoxifen (TAM) and its metabolite 4-hydroxy-tamoxifen (4-OH-TAM). When reduced nicotinamide-adenine dinucleotide phosphate (NADPH) was used as a cofactor in microsomal activation of either 4-OH-TAM or TAM, one DNA adduct and relative DNA adduct levels of 4.6 and 3.1 x 10(-8), respectively were detected by 32P-postlabeling. The DNA adduct produced by microsomal activation of 4-OH-TAM and TAM was the same. With cumene hydroperoxide (CuOOH) as the cofactor for the microsomal activation of either 4-OH-TAM or TAM, three to six DNA adducts were produced; the relative adduct levels were 8.0 and 20.6 x 10(-8), respectively. Comparison of the DNA adduct patterns produced by 4-OH-TAM and TAM showed that they were distinct. However one of the DNA adducts (a) produced by microsomal activation of 4-OH-TAM using CuOOH was the same as adduct a produced by microsomal activation of 4-OH-TAM with NADPH. Activation of 4-OH-TAM with horseradish peroxidase resulted in the formation of a single DNA adduct and a relative adduct level of 20.7 x 10(-8). Rechromatography analysis of this DNA adduct showed that it was identical to that produced by microsomal activation of 4-OH-TAM with NADPH and one of the adducts produced using CuOOH as the cofactor. Ten DNA adducts and a relative adduct level of 15.3 x 10(-8) were detected in the liver of female Sprague-Dawley rats treated daily with 20 mg/kg of TAM for 7 days. The DNA adduct pattern in the liver of the treated animals was similar to that produced by microsomal activation of TAM using CuOOH as the co-factor. The principal DNA adduct (no. 6) formed in the livers of rats treated with TAM was the same as the principal DNA adduct formed following microsomal activation of TAM using CuOOH as a cofactor. The DNA adduct formed following microsomal activation of either TAM or 4-OH-TAM using NADPH was also present as one of the adducts (1) formed in vivo following TAM treatment. These studies demonstrate that 4-OH-TAM can be activated to form DNA adducts and that it contributes to the formation of DNA adducts in the liver of rats treated with TAM.

Animals↗
PubMed1994

32P-post-labeling detection of DNA adducts in mononuclear cells of workers occupationally exposed to styrene.

32P-Post-labeling was used to analyze for the presence of DNA adducts in 47 workers exposed to styrene in a boat manufacturing facility. Individual airborne exposures measured several times over the course of 1 year ranged from 1 to 235 mg/m3 with a mean value of 65.6 mg/m3. Two adducts were detected in the DNA of mononuclear cells of these workers. The following levels of adducts were detected: adduct 1, range 0.6-102 x 10(-8) (mean 15.8 x 10(-8); adduct 2, range 0.1-70.9 x 10(-8) (mean 14.2 x 10(-8). Significant linear relationships were found between styrene exposure and both DNA adducts (adduct 2, r = 0.330, P = 0.012; adduct 1, r = 0.244, P = 0.049). Co-chromatography experiments identified DNA adduct 1 in the exposed samples as N2-(2-hydroxy-1-phenylethyl)-2'-deoxyguanosine-3',5'-bisphosphate. DNA adduct 2 remains unidentified. No significant linear relationships were observed between the level of DNA adducts and sister chromatid exchanges, possibly because of the poor precision of the 32P-post-labeling assay (the estimated coefficients of variation for adducts 1 and 2 were 2.54 and 1.96, respectively). These results demonstrate that occupational exposure to styrene results in the formation of DNA adducts in human mononuclear cells.

DNA↗
PubMed1994

Synthesis of a 25 base oligonucleotide containing a styrene oxide modification at the O6 position of 2'-deoxyguanosine at a defined site and incorporation studies of the similarly modified 2'-deoxyguanosine-5'-triphosphate.

A diastereomeric mixture of the regioisomers O6-(2-hydroxy-2-phenylethyl)-2'-deoxyguanosine (st6G, beta-isomer) and O6-(2-hydroxy-1-phenylethyl)-2'-deoxyguanosine (alpha-isomer) was site-specifically placed in a 25 base oligonucleotide template 5'-CCGCTAst6GCGGGTACCGAGCTCGAAT-3' using CED phosphoramidite chemistry. Using 32P-post-labeling we found the oligonucleotide to contain 95% of the beta-isomer and 5% of the alpha-isomer of st6G. st6G as the 3'-phosphate was found to be considerably more acid labile than O6-methyl-2'-deoxyguanosine-3'-phosphate, leading to dealkylation during oligonucleotide synthesis. The diastereomeric mixture of O6-(2-hydroxy-2-phenylethyl)-2'-deoxy-guanosine-5'-triphosphate (st6dGTP) was chemically synthesized and used as a substrate for the exonuclease-free Klenow fragment of Escherichia coli DNA polymerase I. This study demonstrated that st6dGTP could be incorporated opposite deoxycytidine and did not completely block replication.

Base Sequence↗
PubMed1993

Investigation of benzene-DNA adducts and their detection in human bone marrow.

We have examined DNA adduct formation in HL-60 cells and human bone marrow treated with either hydroquinone or p-benzoquinone and have found that these treatments produce the same DNA adduct in both cell types. The DNA adduct level from these treatments varied from 0.05 to 7.5 adducts per 10(7) nucleotides as a function of treatment time and concentration for both compounds. Reaction of calf thymus DNA with p-benzoquinone produced three adducts as detected by 32P-postlabeling. These adducts have been identified as (3'-hydroxy)-3,N4-benzetheno-2'-deoxycytidine-3'-phosphate; (3'-hydroxy)-1,N6-benzetheno-2'-deoxyadenosine-3'-phosphate; and (3'-hydroxy)-1,N2-benzetheno-2'-deoxyguanosine-3'-phosphate. The DNA adduct formed in HL-60 cells did not correspond to any of the principal adducts formed in DNA reacted with p-benzoquinone, suggesting that cellular environment modifies DNA adduct production by p-benzoquinone. These studies demonstrate that DNA adduct formation occurs in human bone marrow treated with benzene metabolites and suggest that P1-enhanced 32P-postlabeling may be used to detect DNA adducts resulting from benzene exposure.

Benzene↗
PubMed1992

Peroxidative activation of o-phenylhydroquinone leads to the formation of DNA adducts in HL-60 cells.

Using 32P-postlabeling we studied DNA adduct formation in HL-60 cells treated with the o-phenylphenol metabolites o-phenylhydroquinone (o-PHQ) and o-phenylbenzoquinone (o-PBQ). Treatment with 25-500 microM o-PHQ for 8 h produced one principal and three minor adducts with a relative distribution of 80, 10, 6 and 4%. The relative adduct levels from these treatments were 0.26-2.31 adducts/10(7) nucleotides. Treatment with 25-250 microM o-PBQ for 2 h resulted in a similar level of DNA modification and adduct distribution. Reaction of purified calf thymus DNA with o-PBQ produced one DNA adduct, which did not correspond to the major adduct produced in HL-60 cells. These results show that o-PHQ and o-PBQ can form DNA adducts. Peroxidase activation of o-phenylphenol may therefore play a role in the carcinogenic effect of this compound.

Benzoquinones↗
PubMed1992

Identification of N2-substituted 2'-deoxyguanosine-3'-phosphate adducts detected by 32P-postlabeling of styrene-oxide-treated DNA.

Styrene-7,8-oxide, a metabolite of the industrial chemical styrene, was reacted with calf thymus DNA. Six adducts were detected by 32P-postlabeling. The two diastereomers of N2-(2-hydroxy-1-phenylethyl)-2'-deoxyguanosine-3'-phosphate and the corresponding N-1 substituted compounds were isolated from the aqueous reaction mixture of 2'-deoxyguanosine-3'-phosphate and styrene-7,8-oxide (pH 10.5) and characterized by liquid secondary-ion and four-sector tandem mass spectrometry, ultraviolet, circular dichroism, and fluorescence spectrophotometry, and 32P-postlabeling. Co-chromatography of the DNA-styrene-7,8-oxide reaction products with the synthetic standards showed that adduct no. 6 arose as a result of aralkylation at the N2-exocyclic site of the guanine base. The recovery of the N2-adduct was dependent on the concentration of the solvent used during octadecylsilyl chromatography. These studies revealed that the N2-guanosine derivatives are the major products of the reaction of DNA and styrene-7,8-oxide in vitro detected by 32P-postlabeling.

Autoradiography↗
PubMed1991

Detection of DNA adducts in HL-60 cells treated with hydroquinone and p-benzoquinone by 32P-postlabeling.

We have examined DNA adduct formation and cytotoxicity in HL-60 cells treated with either hydroquinone (HQ) or p-benzoquinone (p-BQ). Treatment of HL-60 cells with either HQ or p-BQ produced the same DNA adduct. The DNA adduct level varied from 0.05 to 10 adducts per 10(7) nucleotides as a function of treatment time and concentration for both compounds. To achieve the same DNA adduct level required higher concentrations and longer treatment times with HQ compared to p-BQ. p-BQ was also more cytotoxic to HL-60 cells than HQ. Reaction of calf thymus DNA with a p-BQ/HQ mixture produced five adducts as detected by 32P-postlabeling. Two isomers of (hydroxy)-1,N2-benzetheno-2'- deoxyguanosine-3'-phosphate were isolated from the reaction of 2'-deoxyguanosine-3'-phosphate with a p-BQ/HQ mixture and one of the isomers was identified as adduct no. 1 of the DNA reaction. The DNA adduct formed in HL-60 cells treated with HQ or p-BQ did not correspond to any of the principal adducts formed in DNA reacted with p-BQ/HQ. This result suggests that cellular mechanisms modify DNA adduct formation by HQ and p-BQ.

Benzoquinones↗
PubMed1990

Detection of (3'-hydroxy)-3,N4-benzetheno-2'-deoxycytidine-3'-phosphate by 32P-postlabeling of DNA reacted with p-benzoquinone.

Cytidine-3'-phosphate was reacted with p-benzoquinone under neutral aqueous conditions, and the fluorescent product formed was isolated and characterized. The structure of the covalent adduct was identified as (3'-hydroxy)-3,N4-benzetheno-cytidine-3'-phosphate by high-resolution MS and 1H NMR spectroscopy. A similar product was isolated from the reaction of 2'-deoxycytidine-3'-phosphate with a hydroquinone-p-benzoquinone mixture. 32P-Postlabeling of calf thymus DNA reacted with p-benzoquinone detected several adducts, the principal adduct being (3'-hydroxy)-3,N4-benzetheno-2'-deoxycytidine-3'-phosphate. Our studies demonstrate that the reaction of DNA with p-benzoquinone in vitro leads to multiple DNA adducts. 32P-Postlabeling may allow detection of benzene-DNA adducts in vivo.

Benzoquinones↗
PubMed1989

O6-substituted-2'-deoxyguanosine-3'-phosphate adducts detected by 32P post-labeling of styrene oxide treated DNA.

32P post-labeling of DNA reacted with styrene oxide resulted in the detection of six adducts. In order to determine which of these corresponded to modification at the O6 position of guanine, O6-substituted styrene oxide-deoxyguanosine-3'-monophosphate derivatives were synthesized. The two synthetic isomers were purified by HPLC and the structures were confirmed by mass spectrometry and 1H NMR. 32P post-labeling and co-chromatography with the DNA-styrene-7,8-oxide reaction products resulted in the assignment of adduct number 4 as O6-(2-hydroxy-2-phenylethyl)-2'--deoxyguanosine-3',5'-bisphosphate and adduct number 5 as O6-(2-hydroxy-1-phenylethyl)-2'-deoxyguanosine-3',5'-bisphosphate.

Chemical Phenomena↗
PubMed1988

Detection of styrene oxide-DNA adducts in lymphocytes of a worker exposed to styrene.

The 32P-postlabelling procedure has been used to detect styrene oxide (SO)-DNA adducts. Reactions of SO with DNA and dGMP in vitro produced adducts that were similar, indicating that dGMP was the primary base for modification in DNA. Two SO adducts were also detected in DNA isolated from lymphocytes of a styrene-exposed worker but not in DNA from an unexposed worker. These results indicate that 32P-postlabelling can be used for quantification of DNA adducts in workers exposed to styrene.

DNA↗