Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Hydroxamic Acids”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 955 records · Page 53Linked to original sources
PubMed2004

Isolation and structural characterization of siderophores, madurastatins, produced by a pathogenic Actinomadura madurae.

Madurastatins Al (1), A2 (2) and A3 (3), novel pentapeptides that were acylated with salicylic acid at the N-terminus, were isolated from the culture broth of a pathogenic Actinomadura madurae IFM 0745 strain. These structures were mainly determined by 2D NMR and MS/MS spectral techniques. The strain produced simultaneously madurastatins B1 (4) and B2 (5) consisting of Ser and salicylic acid moieties. Compounds 1 and 4 had an antibacterial activity against Micrococcus luteus, indicating that the presence of the aziridine ring is essential for such activity. Because 1 has a strong affinity with ferric ion due to the presence of two hydroxamic acids and a salicylic acid, it is considered to be a siderophore that is a low molecular weight iron chelater. The production of siderophores may be one of the characteristics of pathogenic microorganisms.

Actinobacteria↗
PubMed1982

Further studies of the suicide inactivation of purified rat liver cytochrome P-450 by chloramphenicol.

The kinetics and reversibility of the suicide inactivation of rat liver cytochrome P-450 by chloramphenicol have been investigated with the use of a reconstituted monooxygenase system purified from liver microsomes of phenobarbital-treated rats. At a ratio of 1 unit of NADPH-cytochrome P-450 reductase per nanomole of cytochrome P-450 and a chloramphenicol concentration of 1 mM, the t1/2 for the inactivation of cytochrome P-450 is less than 2 min. The inactivated cytochrome regains some of its activity upon incubation at 25 degrees or 37 degrees, and experiments with [14C]chloramphenicol show that this partial reactivation is accompanied by the release of some of the 14C originally bound covalently to the cytochrome P-450. Previous work has shown that the 14C-labeled material spontaneously released from 14C-labeled cytochrome P-450 is in the form of oxalic acid, and that the latter is derived from a hydroxylamine-labile adduct of chloramphenicol and cytochrome P-450 [Biochem. Pharmacol. 30:875-881 (1981)]. In the present investigation the 14C-labeled material released by hydroxylamine was identified as the hydroxamic acid of oxalic acid. Trapping experiments with the amino acid cysteine suggest that the adduct, the spontaneous degradation of which appears to be involved in the reactivation of cytochrome P-450, contains an ester rather than a thioester linkage between cytochrome P-450 and a metabolite of chloramphenicol. However, this metabolite may not be identical with chloramphenicol oxamyl chloride, which was the active metabolite implicated in the formation of the 50% covalently bound material which was stable to hydroxylamine treatment.

Animals↗
PubMed1982

Identification of a selenocysteine-specific aminoacyl transfer RNA from rat liver.

The aminoacylation of rat liver tRNA with selenocysteine was studied in tissue slices and in a cell-free system with [75Se]selenocysteine and [75Se]selenite as substrates. [75Se]Selenocysteyl tRNA was isolated via phenol extraction, 1 M NaCl extraction and chromatography on DEAE-cellulose. [75Se]Selenocysteyl tRNA was purified on columns of DEAE-Sephacel, benzoylated DEAE-cellulose and Sepharose 4B. In a dual-label aminoacylation with [35S]cysteine, the most highly purified 75Se-fractions were greater than 100-fold purified relative to 35S. These fractions contained less than 0.7% of the [35S]cysteine originally present in the total tRNA. When [35Se]selenocysteyl tRNA was purified from a mixture of 14C-labeled amino acids, over 97% of the [14C]aminoacyl tRNA was removed. The [75Se]selenocysteine was associated with the tRNA via an aminoacyl linkage. Criteria used for identification included alkaline hydrolysis and recovery of [75Se]selenocysteine, reaction with hydroxylamine and recovery of [75Se]selenocysteyl hydroxamic acid and release of 75Se by ribonuclease. The specificity of [75Se]selenocysteine aminoacylation was demonstrated by resistance to competition by a 125-fold molar excess of either unlabeled cysteine or a mixture of the other 19 amino acids in the cell-free selenocysteine aminoacylation system.

Animals↗
PubMed2006

Aromatic sulfide inhibitors of histone deacetylase based on arylsulfinyl-2,4-hexadienoic acid hydroxyamides.

The synthesis of a novel series of potent inhibitors of histone deacetylases is described, based on arylsulfinyl-2,4-hexadienoic acid hydroxyamides and their derivatives. In vitro IC(50) values down to 40 nM were obtained, and several compounds showed inhibition of CEM (human leukemic) cell viability with IC(50) of approximately 1.5 microM, comparable to or better than that of suberoylanilide hydroxamic acid, an inhibitor of histone deacetylase currently in clinical trials.

Amides↗
PubMed2003

Carrier-facilitated bulk liquid membrane transport of iron(III)-siderophore complexes utilizing first coordination sphere recognition.

Carrier-facilitated bulk liquid membrane (BLM) transport from an aqueous source phase through a chloroform membrane phase to an aqueous receiving phase was studied for various hydrophilic synthetic and naturally occurring Fe(III)-siderophore complexes using first coordination sphere recognition. Iron transport systems were designed such that two cis coordination sites on a hydrophilic Fe(III) complex are occupied by labile aquo ligands, while the other four coordination sites are blocked by strong tetradentate ligands (siderophores). The labile aquo coordination sites can be "recognized" by a liquid membrane-bound hydrophobic bidentate ligand, which carries the hydrophilic Fe(III)-siderophore complex across the hydrophobic membrane to an aqueous receiving phase. The system is further designed for uphill transport of Fe(III) against a concentration gradient, driven by anti-port H(+) transport. Three tetradentate siderophore and siderophore mimic ligands were investigated: rhodotorulic acid (H(2)L(RA)), alcaligin (H(2)L(AG)), and N,N'-dihydroxy-N,N'-dimethyldecanediamide (H(2)L(8)). Flux values for the transport of Fe(L(x))(OH(2))(2)(+) (x = RA, AG, 8) facilitated by the hydrophobic lauroyl hydroxamic acid (HLHA) membrane carrier were the highest when x = 8, which is attributed to substrate lipophilicity. Ferrioxamine B (FeHDFB(+)) was also selectively transported through a BLM by HLHA. The process involves partial dechelation of ferrioxamine B to produce the tetradentate form of the complex (Fe(H(2)DFB)(OH(2))(2)(2+)), followed by ternary complex formation with HLHA (Fe(H(2)DFB)(LHA)(+)) and transport across the membrane into the receiving phase. Uphill transport of ferrioxamine B was confirmed by increased flux as [H(+)](source phase) < [H(+)](receiving phase). The membrane flux of ferrioxamine B occurs near neutral pH, as evidence that ternary complex formation and ligand exchange are viable processes at the membrane/receptor surface of microbial cells.

Deferoxamine↗
PubMed2000

[A 1-hydroxyindole-2-carboxylic acid and a 9-hydroxy-beta-carboline-4-carboxylic acid from a nifedipine analog biscyanoethyl ester].

Bis(2-cyanoethyl) 2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate (3) reacts with sodium hydroxide solution to yield the 1-hydroxyindole-2-carboxylic acid 7 and the 9-hydroxy-beta-carboline-4-carboxylic acid 13. The structures of 7 and 13 were elucidated by derivatization and by spectroscopic methods. Bis(2-cyanoethyl) 2,6-dimethyl-4-(2-nitrosophenyl)pyridine-3,5-dicarboxylate (22) obtained by irradiation of 3 reacts with sodium hydroxide solution to give the cyclic hydroxamic acid 23 whose structure is proven by an independent synthesis.

Carbolines↗
PubMed1981

Significance of metabolic activation and binding to nucleic acids of aminostilbene derivatives in vivo.

Comparison of metabolite binding of several aminostilbene-related compounds to rat liver macromolecules in vivo supported the concept that metabolic activation is a prerequisite for biologic activity. Carcinogenic trans-4-dimethylaminostilbene and trans-4-acetylaminostilbene bound more strongly to DNA than the biologically less active cis-4-acetylaminostilbene and 4-dimethylaminobibenzyl by more than ten times. Hydroxamic acid esters did not appear to be the major metabolites which ultimately reacted with nucleic acids. The primary biochemical lesions are not correlated with tissue susceptibility. Total binding of trans-4-dimethylaminostilbene metabolites to nucleic acids was highest in the liver, about one-fifth of that total amount in the kidney, less than one-fifth in the lung and glandular stomach (which is the target tissue for acute toxicity), and still less in the forestomach and Zymbal's gland, the tissue in which tumors arise after repeated administration of test compounds to female Wistar rats. In the nontarget tissues, i.e., liver and kidney, nucleic acid binding was not only initially high but also persistent. Therefore, the exposure-related, primary biochemical lesion could not be linked to the biologic lesion. Tissue-specific parameters, other than those related to metabolic activation, are proposed to determine the biologic effect.

Animals↗
PubMed2000

Phosphoglyceride crystal deposition disease.

An extremely rare phosphoglyceride deposition disease is reported. A healthy 62-year-old Japanese woman suffered from tumors that repeatedly appeared in injured soft tissues for more than 20 years. No immunologic disorders or abnormal laboratory data were found. Histology showed foreign body granulomas consisting of macrophages surrounding yellowish-white crystals. The crystals were weakly positive by von Kossa's method, were dissolved in 30% acetic acid with gas, and were easily dissolved in 0.1 N NaOH or potassium hydroxide, losing their crystal structure. Using a scanning electron microscopy X-ray microanalyzer, phosphorus and calcium peaks were detected. Phosphoglycerides were detected by microscopic infrared spectrophotometry and microsampling mass spectrometry. The gold hydroxamic acid method for detecting phosphoglyceride showed strong positive staining in the crystals. Based on the above analyses, the deposited crystals were regarded as phosphoglyceride, which bound calcium as a counter ion. The crystals tended to be deposited at sites of injury, where macrophages had accumulated. The patient had received many injections of a medicine made from alcohol extract from bovine liver. We suspect that this medicine was related to the cause of the deposition as the deposition repeatedly appeared at the site of the injections.

Connective Tissue↗
PubMed1996

2.3 A resolution X-ray crystal structure of the bisubstrate analogue inhibitor salicylhydroxamic acid bound to human myeloperoxidase: a model for a prereaction complex with hydrogen peroxide.

The X-ray crystal structure of a salicylhydroxamic acid (SHA) inhibitory complex with human myeloperoxidase (MPO) has been determined at 2.3 A resolution. The aromatic ring of the inhibitor binds to a hydrophobic region at the entrance to the distal heme pocket between heme pyrrole ring D and the side chain of Arg 239. The hydroxamic acid moiety is hydrogen bonded to both the distal histidine 95 and the adjacent glutamine 91 amide group but is not coordinated to the heme iron. SHA binding displaces three water molecules from the distal heme cavity and causes a small shift in the position of a fourth water molecule. Otherwise, there are no significant conformational differences between the active site regions of the complex and the native enzyme. The ability of the three SHA oxygen atoms to closely duplicate the hydrogen-bonding pattern of these three water molecules in the native enzyme is postulated to account for the strong binding of this inhibitor to MPO. The mode of binding of SHA to MPO provides information on the binding sites for aromatic peracid substrates that promote compound I formation as well as aromatic alcohols and amines that carry out single-electron reductions of compound I. Similarities in the hydrogen-bonding patterns of amino acid residues and water molecules in the distal heme pockets of myeloperoxidase and the nonhomologous cytochrome c peroxidase suggest that they may have similar mechanisms of compound I formation. A model is presented for a prereaction complex of myeloperoxidase in which hydrogen peroxide is hydrogen bonded to the distal histidine, as a prerequisite for deprotonation and subsequent binding at the sixth coordination site of the heme iron.

Crystallography, X-Ray↗
PubMed1989

Distinct lipoxygenase species appear in the hypocotyl/radicle of germinating soybean.

Three lipoxygenase isozymes are synthesized in developing soybean (Glycine max [L.] Merr. cv Williams) embryos and are found in high levels in cotyledons of mature seeds (B Axelrod, TM Cheesbrough, S Zimmer [1981] Methods Enzymol 71: 441-451). Upon germination at least two new protein species appear which are localized mainly (on a protein basis) in the hypocotyl/radicle section. These lipoxygenase species appear also in seedlings of each of three lipoxygenase nulls (1x1, 1x2, and 1x3) deficient in one of the dormant seed lipoxygenases. The germination-associated species are distinguishable from dry seed lipoxygenase by their more acidic isoelectric points as revealed in isoelectric focusing gels. They are active from as early as 2 to at least 5 days after the start of imbibition. These germination-stimulated species qualify as lipoxygenase by their inhibition by the lipoxygenase inhibitors n-propyl gallate and salicyl hydroxamic acid and their lack of inhibition by KCN. Further, they are not active on the peroxidase substrate pair H(2)O(2)/3-amino-9-ethyl carbazole. They are recognized on Western blots by polyclonal antibodies to the seed lipoxygenase-1 isozyme and the major induced species has a molecular weight of approximately 100,000, similar to that of the cotyledon lipoxygenases. These lipoxygenases appear to be synthesized de novo upon germination since they comigrate with radioactive protein species from seeds germinated in [(35)S]methionine.

Journal Article↗
PubMed2000

Evidence for production of hydroxyl radicals by pentachlorophenol metabolites and hydrogen peroxide: A metal-independent organic Fenton reaction.

The production of hydroxyl radicals by tetrachlorohydroquinone (TCHQ, a major metabolite of the widely used biocide pentachlorophenol) in the presence of H(2)O(2) was studied by salicylate hydroxylation method. HPLC with electrochemical detection was used to measure the levels of 2,3- and 2,5-dihydroxybenzoic acid (DHBA) formed when the hydroxyl radicals react with salicylate. We found that TCHQ and H(2)O(2) could produce both 2,3- and 2,5-DHBA when incubated with salicylate. Their production was markedly inhibited by hydroxyl radical scavenging agents dimethyl sulfoxide and ethanol, as well as by tetrachlorosemiquinone radical scavengers desferrioxamine and other hydroxamic acids. In contrast, their production was not affected by the nonhydroxamate iron chelators diethylenetriaminepentaacetic acid (DTPA), bathophenanthroline disulfonic acid, and phytic acid, as well as the copper-specific chelator bathocuprione disulfonic acid. A comparison of product formation and distribution from the reaction of ferrous iron with hydrogen peroxide (the classic Fenton system) strongly suggests that the same hydroxyl radical adducts are formed as in the TCHQ/H(2)O(2) experiments. Taken together, we propose that hydroxyl radicals were produced by TCHQ in the presence of H(2)O(2), probably through a metal-independent organic Fenton reaction.

Chelating Agents↗
PubMed2002

Transforming growth factor beta mimetics: discovery of 7-[4-(4-cyanophenyl)phenoxy]-heptanohydroxamic acid, a biaryl hydroxamate inhibitor of histone deacetylase.

Transforming growth factor beta (TGF-beta) is a multifunctional protein that has been shown to possess potent growth-inhibitory activity. To identify small molecular weight compounds with TGF-beta-like activities, high throughput screening was performed using mink lung epithelial cells stably transfected with a TGF-beta-responsive plasminogen activator inhibitor 1 promoter/luciferase construct. Biaryl hydroxamate compounds were identified that demonstrated TGF-beta-like activities. 7-[4-(4-cyanophenyl)phenoxy]-heptanohydroxamic acid (A-161906) demonstrated complete TGF-beta-like agonist activity in the plasminogen activator inhibitor 1/luciferase construct. A-161906 inhibited the proliferation of multiple cell lines in a concentration-dependent manner. Cells were growth arrested at the G1-S checkpoint similar to TGF-beta. Consistent with the G1-S arrest, A-161906 induced the expression of the cyclin-dependent kinase inhibitor p21waf1/cip1. A-161906 produced many cellular effects similar to that of TGF-beta but did not displace labeled TGF-beta from its receptors. Cells with mutations in either of the TGF-beta receptors I or II were growth-arrested by A-161906. Therefore, the site of action of A-161906 appears to be distal to the receptors and possibly involved with the signaling events controlled by TGF-beta. The TGF-beta mimetic effect of A-161906 can be partially, if not entirely, explained by its activity as a histone deacetylase (HDAC) inhibitor. A-161906 demonstrated potent HDAC-inhibitory activity (IC50 = 9 nM). A-161906 is a novel small molecular weight compound (< 400 MW) having TGF-beta mimetic activity as a result of its potent HDAC-inhibitory activity. These results and those of others demonstrate the importance of HDACs in regulation of the TGF-beta signaling pathway(s).

Acetylation↗
PubMed1993

N-n-alkyl-3,4-dihydroxybenzamides as inhibitors of the trypanosome alternative oxidase: activity in vitro and in vivo.

On the basis of our previous demonstration of the high inhibitory activity of a series of p-n-alkyloxybenzhydroxamic acids and n-alkyl esters of 3,4-dihydroxybenzoic acid against the trypanosome alternative oxidase in a cell-free mitochondrial preparation of Trypanosoma brucei brucei, we synthesized a series of N-n-alkyl-3,4-dihydroxybenzamides for evaluation as inhibitors of this enzyme. This class of compounds was selected with the expectation of their having similar inhibitory activity to but greater solubility than the esters and hydroxamic acids noted above and greater resistance to serum hydrolases in vivo. We predicted that such properties would allow an inhibitor of the trypanosome alternative oxidase to be coadministered with glycerol as a means of providing treatment for infections by African trypanosomes. As expected, such benzamides were both more soluble and more stable, some being more active against the target enzyme than the corresponding ester. One, N-n-butyl-3,4-dihydroxybenzamide, was selected for evaluation in vivo against T. brucei brucei. When combined with glycerol, this benzamide was found to be curative. A regimen wherein 450 mg of N-n-butyl-3,4-dihydroxybenzamide per kg and 15 g of glycerol per kg were given hourly in three divided doses cured 17 of 19 mice with established T. brucei brucei infections. This combination is more active in vivo than any other designed to block simultaneously both the unique respiratory electron transport system and the anaerobic glycolytic pathways of these pathogenic protozoa.

Animals↗
PubMed1990

Molecular modeling studies on the urease active site and the enzyme-catalyzed urea hydrolysis.

These studies are an attempt to gain better insight into the pharmacophore requirements of urease. On the basis of published information on this enzyme (EXAFS, amino acid sequence, essential groups at the active site) a hypothetical nickel-tripeptide complex, as preliminary substitute for the urease active site was modeled using computer-aided molecular modeling techniques. The results suggest two alternative docking modes of urea and reaction intermediates, corresponding to two different reaction mechanisms. Both binding modes are compatible with the docking of known potent inhibitors such as selected hydroxamic acids and phosphorodiamides. The results can be used to help in the design of new potential inhibitors of urease.

Binding Sites↗
PubMed2003

[Pyrano[3,4-c]quinolines from 1-desaza--oxa-nifedipine].

Pyrano[3,4-c]quinolines from 1-desaza-1-oxa-nifedipine The reaction of the 1,5-diketone 1 with acetic anhydride/acetic acid in the presence of zinc chloride yields the 1-desaza-1-oxa-nifedipine 2 and the annulated lactone 3 as a by-product. The structures of 2 and 3 are confirmed by X-ray structure analysis. The pH-dependent reduction of the nitro group from 2 leads to the pyrano[3,4-c]quinolines 4Aa, b by ring closure. The cyclic hydroxamic acid 4Aa represents a weak, non-selective inhibitor of 5-, 12- and 15-lipoxygenase of human full-blood.

Chromatography, High Pressure Liquid↗
PubMed2003

Protease inhibitors: synthesis of bacterial collagenase and matrix metalloproteinase inhibitors incorporating arylsulfonylureido and 5-dibenzo-suberenyl/suberyl moieties.

Novel matrix metalloproteinase (MMP)/bacterial collagenase inhibitors are reported, considering the sulfonylated amino acid hydroxamates as lead molecules. A series of compounds was prepared by reaction of arylsulfonyl isocyanates with N-(5H-dibenzo[a,d]cyclohepten-5-yl)- and N-(10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5-yl) methyl glycocolate, respectively, followed by the conversion of the COOMe to the carboxylate/hydroxamate moieties. The corresponding derivatives with methylene and ethylene spacers between the polycyclic moiety and the amino acid functionality were also obtained by related synthetic strategies. These new compounds were assayed as inhibitors of MMP-1, MMP-2, MMP-8 and MMP-9, and of the collagenase isolated from Clostridium histolyticum (ChC). Some of the new derivatives reported here proved to be powerful inhibitors of the four MMPs mentioned above and of ChC, with activities in the low nanomolar range for some of the target enzymes, depending on the substitution pattern at the sulfonylureido moiety and on the length of the spacer through which the dibenzosuberenyl/suberyl group is connected with the rest of the molecule. Several of these inhibitors also showed selectivity for the deep pocket enzymes (MMP-2, MMP-8 and MMP-9) over the shallow pocket ones MMP-1 and ChC.

Arylsulfonates↗
PubMed1985

DNA adducts formed from the probable proximate carcinogen, N-hydroxy-3,2' -dimethyl-4-aminobiphenyl, by acid catalysis or S-acetyl coenzyme A-dependent enzymatic esterification.

The arylamine carcinogen 3,2'-dimethyl-4-aminobiphenyl (DMABP) has been proposed to be metabolically activated to DNA-binding derivatives through the formation of an N-hydroxy intermediate. In this study, the subsequent activation of N-hydroxy-DMABP through acid catalysis or enzymatic esterification was examined. [Ring-3H]N-hydroxy-DMABP was reacted with calf thymus DNA at pH 4.6 for 15 min to yield 370 arylamine residues per 10(6) nucleotides, while at pH 7.4 the binding was only two residues per 10(6) nucleotides. The DNA modified under acidic conditions was enzymatically hydrolyzed and analyzed by h.p.l.c. which indicated the presence of three major adducts. The products were identified by spectral and chemical properties as N-(deoxyguanosin-8-yl)-DMABP (60-70%), 5-(deoxyguanosin-N2-yl)-DMABP (2-3%) and N-(deoxyadenosin-8-yl)-DMABP (1-3%). The same adducts have previously been detected in the liver and colon of rats administered DMABP or its hydroxamic acid. Incubation of rat hepatic or intestinal cytosol at pH 7.4 for 15 min with [ring-3H]N-hydroxy-DMABP in the presence of S-acetyl coenzyme A (AcCoA) and calf thymus DNA resulted in DNA binding at levels of 30-80 arylamine residues per 10(6) nucleotides. H.p.l.c. analysis of the DNA modified in the presence of AcCoA indicated the formation of the same adducts detected in the acid-catalyzed reactions. When arylhydroxamic acid N,O-acyltransferase assays were conducted with rat liver cytosol and N-acetyl-N-hydroxy-DMABP as the substrate, binding to nucleic acids was not observed. Similarly, 3'-phosphoadenosine-5'-phosphosulfate-dependent sulfotransferase-mediated DNA binding could not be demonstrated. These data indicate that in a suitable acidic environment, N-hydroxy-DMABP will react with DNA to yield the same adducts found in vivo. Under neutral conditions, however, N-hydroxy-DMABP appears to undergo AcCoA-dependent transacetylation to an electrophilic acetoxy ester which will spontaneously react with DNA.

Acetyl Coenzyme A↗
PubMed1993

Characterization of various classes of protein adducts.

Analysis of the types of protein adducts formed by chemical carcinogens indicate that adducts may be categorized into various classes according to the nature of the carcinogen as well as the amino acid with which they react. Tryptophan(214) of serum albumin was previously shown to react specifically with N-sulfonyloxy-N-acetyl-4-aminobiphenyl. The same residue is now shown to also react with the sulfate esters of N-hydroxy-N-acetyl-2-aminofluorene and N-hydroxy-N,N'-diacetylbenzidine. Thus, Trp-214 appears to be a binding site for a variety of activated N-aryl hydroxamic acids. Epoxides and diol epoxides derived from polynuclear aromatic hydrocarbons alkylate carboxylic groups in hemoglobin and serum albumin. Because the esters formed are readily hydrolyzed to dihydrodiols and tetrahydrotetrols which can be determined by GC-MS, it is possible to analyze for a wide range of polyaromatic hydrocarbon (PAH) epoxide adducts. With this approach it was shown that human subjects experiencing exposure to ambient levels of environmental PAH do take up and metabolize chrysene and benzo[a]pyrene. Feral, bottom-dwelling fish inhabiting contaminated waters were also examined. Globin adducts containing certain dihydroxy groups such as those arising in anti-diol epoxide adducts were concentrated by boronate affinity chromatography and further analyzed by HPLC with diode-array UV/visible detection. Four compounds were detected that exhibited spectra characteristic of a polynuclear chromophore. Two of these appeared to be isomers. Further instrumental analysis is needed to elucidate the structure of these unknown putative adducts.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗