共查询到20条相似文献,搜索用时 31 毫秒
1.
A. Meyer J. Schmidt D. Gross E. Jensen A. Rudolph S. Vorkefeld G. Sembdner 《Journal of Plant Growth Regulation》1991,10(1-4):17-25
The biotransformation of [2-14C](±)9, 10-dihydrojasmonic acid (DJA) was studied in excised shoots of 6-day-old barley seedlings after 72 h. From the ethyl acetate extract, some minor metabolites were isolated and purified by DEAE-Sephadex A-25 chromatography, thin-layer chromatography (TLC), C18-cartridges, and high-performance liquid chromatography (HPLC). The structural identification of these metabolites was performed by gas chromatography-mass spectrometry (GC-MS), circular dichroism (CD), and amino acid analysis, and the following amino acid conjugates were found:N-[(?)9,10-dihydrojasmonoyl]valine,N-[(?)9,10-dihydrojasmonoyl]isoleucine,N-[9,10-dihydrojasmonoyl]leucine,N-[11-hydroxy-9,10-dihydrojasmonoyl]valine,N-[11-hydroxy-9,10-dihydrojasmonoyl]isoleucine,N-[12-hydroxy-9,10-dihydrojasmonoyl]isoleucine; and the cucurbic acid-related compoundsN-{[3-hydroxy-2(4-hydroxypentyl)-cyclopent-1-yl]-acetyl}isoleucine andN-{[3-hydroxy-2(5-hydroxypentyl)-cyclopent-1-yl]-acetyl}isoleucine. The results suggest conjugation with isoleucine and valine, as well as preferential hydroxylation at position C-11 or hydrogenation at position C-6, as being important steps in the metabolism of (±)DJA in barley shoots. 相似文献
2.
Masanobu Kawanishi Takeji Enya Hitomi Suzuki Hiraku Takebe Saburo Matsui Takashi Yagi 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2000,470(2):602
3-Nitrobenzanthrone (NBA) is one of the most mutagenic nitroaromatic compounds that has been found recently in diesel exhaust and airborne particles. A [32P]-postlabelling analysis was carried out to examine the adducts in DNA from human hepatoma HepG2 cells treated with NBA. Two major and two minor adduct spots were obtained in the analysis. The structure of the compound obtained from one of the minor adduct spots was identified to be N-acetyl-3-amino-2-(2′-deoxyguanosin-3′,5′-bisphosphate-8-yl)-benzanthrone, based on identical mobility of the compound with that of synthetic standards in thin-layer chromatography and high performance liquid chromatography. This substance is the identical adduct found in our previous in vitro study. The yet-unidentified major adduct spots may be guanosin- and adenosin-benzanthrone adducts without the N-acetyl group. 相似文献
3.
Jonathan D. Crane Lucy C. Emeleus David Harrison Paul A. Nilsson 《Inorganica chimica acta》2004,357(11):3407-3412
The Schiff base, non-symmetrical, compartmental ligand N-[5-(2-{[2-hydroxy-3-methoxy-phenyl-methylidene]-amino}-phenyl-sulfamoyl)-[1,3,4]thiadiazol-2-yl]-acetamide (H3L) has been prepared by condensation of the acetazolamide derivative N-[5-(2-amino-phenylsulfamoyl)-[1,3,4]thiadiazol-2-yl]-acetamide (3) with 2-hydroxy-3-methoxy-benzaldehyde. The complexation of H3L with cobalt(II) chloride in pyridine under aerobic conditions yielded [CoIII(HL)(py)2][CoII(py)Cl3] · CH3CH2OH (4). The single crystal X-ray structures of H3L and 4 are reported. In the mononuclear cation [CoIII(HL)(py)2]+ of 4 the octahedral cobalt(III) ion is bound at the inner, metal ion binding site, and the larger, empty, outer metal binding site is partly occupied by the hydrogen-bonded ethanol molecule of crystallisation. 相似文献
4.
Occurrence and identification of jasmonic acid and its amino acid conjugates induced by osmotic stress in barley leaf tissue 总被引:9,自引:0,他引:9
R. Kramell R. Atzorn G. Schneider O. Miersch C. Brückner J. Schmidt G. Sembdner B. Parthier 《Journal of Plant Growth Regulation》1995,14(1):29-36
The effect of osmotically active substances on the alteration of endogenous jasmonates was studied in barley (Hordeum vulgare L. cv. Salome) leaf tissue. Leaf segments were subjected to solutions of d-sorbitol, d-mannitol, polyethylene glycol 6000, sodium chloride, or water as a control. Alterations of endogenous jasmonates were monitored qualitatively and quantitatively using immunoassays. The structures of jasmonates isolated were determined on the basis of authentic substances by capillary gas chromatography-mass spectrometry. The stereochemistry of the conjugates was confirmed by high performance liquid chromatography with diastereoisomeric references. In barley leaves, jasmonic acid and its amino acid conjugates, for example, with valine, leucine, and isoleucine, are naturally occurring jasmonates. In untreated leaf segments, only low levels of these native jasmonates were found. After treatment of the leaf tissues with sorbitol, mannitol, as well as with polyethylene glycol, an increase of both jasmonic acid and its conjugates could be observed, depending on the stress conditions used. In contrast, salt stress was without any stimulating effect on the levels of endogenous jasmonates. From barley leaf segments exposed to sorbitol (1m) for 24 h, jasmonic acid was identified as the major accumulating compound. Jasmonic acid-amino acid conjugates increased likewise upon stress treatment.Abbreviations JM
methyl jasmonate
- JA
jasmonic acid
- JIP(s)
jasmonate-induced protein(s)
- PEG
polyethylene glycol
- RIA
radioimmunoassay
- ELISA
enzyme-linked immunosorbent assay
- HPLC
high performance liquid chromatography
- GC-MS
gas chromatography-mass spectrometry
-
R
t
retention time
- IAA
indole-3-acetic acid 相似文献
5.
N-Acetyl-D-[2-3H]glucosamine was synthesized from N-acetyl-D-mannosamineby alkaline 2-epimerization in pyridine containing 3H2O andnickelous acetate. The reaction involves reversible formationof an enol intermediate and therefore also resulted in incorporationof tritium into N-acetylmannosamine. After completed reaction,the two N-acetylhexosamines were separated from other radioactiveproducts and Morgan-Elson chromogens by chromatography on acolumn of Sephadex G-10, which was eluted with 10% ethanol,and were then separated from each other by chromatography onSephadex G-15 in 0·27 M sodium borate (pH 7·8).The location of the incorporated tritium was established bytreatment of the N-acetylhexosamines with borate under the conditionsof the Morgan-Elson reaction, which converts the sugars to Kuhn'schromogen I with concomitant loss of the C-2 hydrogen. As expected,this treatment resulted in the formation of 3H2O, indicatingthat the tritium was located at C-2. [2-3H]Glucosamine was preparedby acid hydrolysis of the labelled N-acetylglucosamine and wasconverted to [2-3H]glucosamine 6-phosphate by incubation withhexokinase and ATP. The sugar phosphate was used as a substratefor glucosamine 6-phosphate deaminase (isomerase, EC 5.3.1.10
[EC]
)in a simple 3H2O release assay. N-acetyl[2-3H]glucosamine N-acetyl[2-3H]mannosamine [2-3H]glucosamine glucosamine 6-phosphate deaminase [2-3H]mannosamine 相似文献
6.
《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):1163-1165
Abstract Synthesis of (1S,3R,4R,7R)-7-hydroxy-1-hydroxymethyl-3-(6-N-benzoyl-adenin-9-yl)-2,5-dioxabicyclo[2.2.1]heptane (2), a base-protected xylo-LNA adenine nucleoside, has been accomplished using a convergent synthetic strategy starting from 1,2-di-O-acetylfuranose 3. 相似文献
7.
《Nucleosides, nucleotides & nucleic acids》2013,32(5-8):1155-1157
Abstract Synthesis of (1R,3R,4S,7R)-7-hydroxy-1-hydroxymethyl-3-(2-N-isobutyroylguanin-9-yl)-2,5-dioxabicyclo[2.2.1]heptane (12), a protected α-L-LNA guanine nucleoside, has been accomplished using a convergent synthetic strategy starting from 1,2-di-O-acetylfuranose 4. 相似文献
8.
Sh. H. Abdel-Hafez 《Russian Journal of Bioorganic Chemistry》2010,36(3):370-376
Synthesis of 3-[4-(N-substituted sulfamoyl)phenyl]-3,4-dihydro-4-oxo-7,9-dimethylpyri-do[3′,2′:4,5]selenolo[3,2-d]pyrimidines,7-[4-(N-substituted sulfamoyl)phenyl]-7,8-dihydro-8-oxo-3,4-diphenylpyrimido[4′,5′:4,5]selenolo [2,3-c]pyridazines and 1-[4-(N-substituted sulfamoyl)phenyl]-1,11-dihydro 11-oxo-4-methylpyrimido[4′,5′:4,5]selenolo[2,3-b]quinolines is reported. 4-Amino-N-pyrimidine-2-ylbenzene sulfonamide (a), 4-amino-N-(2,6-dimethylpyrimidin-4-yl)benzene sulfonamide (b), N-[(4-aminophenyl)sulfonyl] acetamide (c) with N-ethoxymethyleneamino of selenolo pyridine, selenolo pyridazine and selenolo quinoline derivatives respectively were obtained
starting from 1-amino-N
4-substituted sulfanilamides. Spectroscopic data (IR, 1H NMR, 13C NMR and Mass spectral) confirmed the structure of the newly synthesized compounds. Substituted
pyrimidines, pyridazines and quinolines were screened for antibacterial activity against gram-positive and gram-negative bacteria. Selenolo derivative of N-[(4-aminophenyl)sulfonyl] acetamide (substitutent of sulfacetamide c) showed strong bactericidal effect against all the tested
organisms. Selenolo[3,2-d]pyrimidin (substitutent a) showed a good bactericidal effect against Serratia marcescens, Staphylococcus aureus and Escherichia coli. Compounds selenolo[2,3-c]pyridazine (substitutent b), selenolo[2,3-b]quinoline(substitutents c)) exhibited a moderate bactericidal effect against Serratia marcescens. None of the synthesized seleno pyridazines has a considerable antimicrobial activity against the tested organisms. The minimum
inhibitory concentration (MIC) of the most active compound-3-[4-(N-acetyl sulfamoyl)phenyl]-3,4-dihydro-4-oxo-7,9-dimethylpyrido[3′,2′:4,5]selenolo [3,2-d]pyrimidine was 10 mg ml−1. 相似文献
9.
In the present work, a theoretical study of five bipyrazolic-type organic compounds, 4-{bis[(3,5-dimethyl-1H-pyrazolyl-1-yl)methyl]-amino}phenol (1), N1,N1-bis[(3,5-dimethyl-1H-pyrazol-1-yl)methyl}]-N4,N4-dimethyl-1,4-benzenediamine (2), N,N-bis[(3,5-dimethyl-1H-pyrazol-1-yl)methyl]aniline (3), 4-[bis(3,5-dimethyl pyrazol-1-yl-methyl)-amino]butan-1-ol (4) and ethyl4-[bis(3,5-dimethyl-1H-pyrazol-1-yl-methyl) aminobenzoate] (5), has been performed using density functional theory (DFT) at the B3LYP/6-31G(d) level in order to elucidate the different inhibition efficiencies and reactive sites of these compounds as corrosion inhibitors. The efficiencies of corrosion inhibitors and the global chemical reactivity relate to some parameters, such as EHOMO, ELUMO, gap energy (ΔE) and other parameters, including electronegativity (χ), global hardness (η) and the fraction of electrons transferred from the inhibitor molecule to the metallic atom (ΔN). The calculated results are in agreement with the experimental data on the whole. In addition, the local reactivity has been analyzed through the Fukui function and condensed softness indices. 相似文献
10.
Giorgos A Fragkiadakis Emmanoel K Stratakis 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》1997,117(4):545-552
A lectin that recognized sialic acids and agglutinated mouse erythrocytes was purified from hemolymph of the crab Liocarcinus depurator. It consisted of 38-kDa subunits and had a pI about 6.0. The specificity of the lectin was assayed by hemagglutination inhibition. N-acetylneuraminic acid (Neu5Ac) was a good inhibitor and its N-acetyl group at C-5 was critical for lectin-ligand interaction. Substitution of the C-9 hydroxyl on Neu5Ac with an O-acetyl group (9-O-Ac-Neu5Ac) increased the inhibitory potency of this molecule. Furthermore, O-acetyl substitution of all the hydroxyl groups yielded even better inhibitors (2,4,7,8,9-O-Ac-Neu5Ac and its 1-O-methyl ester). Removal of the hydroxyl or O-acetyl group connected to C-2 reduced the potency of these inhibitors. The lectin agglutinated and stimulated human but not mouse lymphocytes. It was also inhibited by Escherichia coli (O111:B4) lipopolysaccharide and agglutinated specific gram-negative bacteria. In vitro labeling with [35S]methionine indicated that the lectin was synthesized in hepatopangreas of L. depurator. Immunofluorescence showed that among hemocytes it localized mainly in the large-granule population. 相似文献
11.
Szymańska Aneta Ossowski Tadeusz Łankiewicz Leszek 《International journal of peptide research and therapeutics》2002,9(4-5):193-196
Summary A synthesis ofl-Nɛ-(9,10-dioxo-9,10-dihydroanthracen-1-yl)-lysine [Lys(AQN)], the dabcyl-like chromophore, and its derivatives useful in peptide
chemistry is described. Nα-tert-butoxycarbonyl derivative of the title compound was obtained in a good yield using aromatic nucleophilic substitution reaction.
In this form, or after conversion to the Nα-fluorenylmethoxycarbonyl derivative, it can be directly used in the solid phase peptide synthesis using either Boc- or Fmoc-strategy. 相似文献
12.
Maria Rosa Buemi Laura De Luca Alba Chimirri Stefania Ferro Rosaria Gitto Julio Alvarez-Builla Ramon Alajarin 《Bioorganic & medicinal chemistry》2013,21(15):4575-4580
Several indole derivatives, that were highly potent ligands of GluN2B-subunit-containing N-methyl-d-aspartate (NMDA) receptor, also demonstrated antioxidant properties in ABTS method. In particular, the 2-(4-benzylpiperidin-1-yl)-1-(5-hydroxy-1H-indol-3-yl)ethanone (1) proved to be a dual-effective neuroprotective agent. With the aim to increase the antioxidant properties we added a catechol moiety onto piperidine moiety. The designed hybrid derivative 3,4-dihydroxy-N-[1-[2-(5-hydroxy-1H-indol-3-yl)-2-oxoethyl]piperidin-4-yl]benzamide (10) was the most effective antioxidant agent (>94.1 ± 0.1% of inhibition at 17 μM) and showed GluN2B/NMDA receptor affinity at low micromolar concentration (IC50 0.66 μM). By means of computational studies we explored the effect of the presence of this antioxidant fragment during the recognition process to binding pocket. 相似文献
13.
Jan Lukszo Dale Patterson Fernando Albericio Steven A. Kates 《Letters in Peptide Science》1996,3(3):157-166
Summary Several side reactions have been detected for cysteine-containing peptides. During the synthesis ofC-terminal cysteine peptides, a base-catalyzed elimination of the sulfhydryl-protected side-chain to afford the dehydroalanine derivative followed by a nucleophilic addition to the alkene was observed. MALDI-TOF analysis was a useful analytical technique to determine this phenomenon.Abbreviations Acm
acetamidomethyl
- Boc
tert-butyloxycarbonyl
-
t-Bu
tert-butyl
- DBU
1,8-diazabicyclo[5.4.0]undec-7-ene
- DIEA
N,N-diisopropylethylamine
- DMF
N,N-dimethylformamide
- Fmoc
9-fluorenylmethyloxycarbonyl
- HATU
N-[(dimethylamino)-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl-methylene]-N-methylmethanaminium hexafluorophosphateN-oxide
- HBTU
N-[(1H-benzotriazol-1-yl)(dimethylamino)methylene]-N-methylmethanaminium hexafluorophosphateN-oxide
- HOAt
1-hydroxy-7-azabenzotriazole
- HOBt
1-hydroxybenzotriazole
- HPLC
high-performance liquid chromatography
- MALDI-TOF
matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
- PAC
4-hydroxymethylphenoxyacetic acid handle
- PAL
5-(4-(9-fluorenylmethyloxycarbonyl)aminomethyl-3,5-dimethoxy-phenoxy)valeric acid handle
- PEG-PS
polyethylene glycol-polystyrene graft supports
- PS
polystyrene
- Reagent R
TFA/thioanisole/1,2-ethanedithiol/anisole (90:5:3:2)
- S-t-Bu
S-tert-butyl mercapto
- TFA
trifluoroacetic acid
- Trt
triphenylmethyl. Amino acid symbols denote thel-configuration, unless indicated otherwise 相似文献
14.
15.
Robin E. Mitchell 《Phytochemistry》1985,24(2):247-249
Addition of either l-[U-14C]threonine or l-[U-14C]isoleucine to 2.7-day-old shaking liquid cultures of Pseudomonas syringae pv. atropurpurea resulted in incorporation of radioactivity into coronatine, but not into N- coronafacoylvaline, another phytotoxin excreted by P.s. atropurpurea. In contrast, addition ofl-[U-14C]valine did not lead to incorporation of radioactivity into coronatine, but instead into coronafacoylvaline. Acid hydrolysis of the purified [14C] coronatine obtained after incorporation of either [14C]isoleucine or [14C]threonine demonstrated that > 94% of the radioactivity was present in the 1-amido-1-carboxy-2-ethylcyclopropyl moiety of coronatine, and < 6 % was in the coronafacoyl moiety. These findings are used to propose a biosynthetic pathway for coronatine. 相似文献
16.
Previous studies have shown that the carcinogen N-hydroxy-2-acetylaminofluorene is converted by one-electron oxidants to a free nitroxide radical which dismutates to N-acetoxy-2-acetylaminofluorene and 2-nitrosofluorene. The present study shows that the same oxidation can be achieved with horseradish peroxidase and H2O2. The free radical intermediate was detected by its ESR signal, and the yields of N-acetoxy-2-acetylaminofluorene and of 2-nitrosofluorene were determined under a number of conditions. Addition of tRNA to the reaction mixture containing N-acetoxy-N-2-acetyl[2′-3H]aminofluorene yielded tRNA-bound radioactivity; addition of guanosine yielded a reaction product which appears to be N-guanosin-8-yl)-2-acetylaminofluorene. The latter compound has previously been identified as a reaction product of N-acetoxy-2-acetylaminofluorene and guanosine. Preliminary attempts to demonstrate the formation of a nitroxide free radical or its dismutation products with rat liver mixed function oxidase systems were not successful. 相似文献
17.
Novel mono-O-acetylated GM3s, one containing 9-O-acetylN-glycolyl neuraminic acid and another containing 6-O-acetyl galactose, were isolated as a mixture from equine erythrocytes, and the structures were characterized by one- and two-dimensional proton nuclear magnetic resonance (NMR) and fast atom bombardment-mass spectrometry (FAB-MS). The position of theO-acetyl residue was identified by the downfield shift of the methylene protons at C-9 ofN-glycolyl neuraminic acid (9-O-Ac GM3) and C-6 of galactose (6-O-Ac GM3) in the NMR spectrum, in comparison to the respective non-acetylated counterparts. To confirm the presence of 6-O-Ac GM3, theO-acetylated GM3 mixture was desialylated withArthrobacter neuraminidase, giving 6-O-acetyl galactosyl glucosylceramide, the structure of which was estimated by NMR and FAB-MS, together with non-acetylated lactosylceramide with a ratio of 1:1.
Abbreviations: Ac, acetyl; Gc, glycolyl; NeuGc,N-Gc neuraminic acid; GM3 (Gc), GM3 containing NeuGc (II3NeuGc-LacCer); 4-O-Ac GM3 (Gc), GM3 containing 4-O-Ac NeuGc; 9-O-Ac GM3 (Gc), GM3 containing 9-O-Ac NeuGc; 6-O-Ac GM3 (Gc), GM3 containing 6-O-Ac Gal; 1D-NMR, one-dimensional nuclear magnetic resonance spectrometry; 2D-COSY, two-dimensional chemical shift-correlated spectrometry; FAB-MS, fast atom bombardment-mass spectrometry; GLC, gas-layer chromatography; GC-MS, gas chromatography-mass spectrometry; TLC, thin-layer chromatography; Ggl, ganglioside; Cer, ceramide; CMH, monohexosylceramide; LacCer, lactosylceramide; 6-O-Ac LacCer, LacCer containing 6-O-Ac Gal; Me2SO-d6,2H6-dimethylsufloxide; CMW, chloroform-methanol-water; Nomenclature and abbreviations of glycosphingolipids follow the system of Svennerholm (J Neurochem [1963]10: 613–23) and those recommended by the IUPAC-IUB Nomenclature Commission (Lipids [1977]12: 455–68). 相似文献
18.
John B. Sutherland James P. Freeman Allison L. Selby Peter P. Fu Dwight W. Miller Carl E. Cerniglia 《Archives of microbiology》1990,154(3):260-266
The metabolism of phenanthrene, a polycyclic aromatic hydrocarbon (PAH), by Streptomyces flavovirens was investigated. When grown for 72 h in tryptone yeast extract broth saturated with phenanthrene, the actinomycete oxidized 21.3% of the hydrocarbon at the K-region to form trans-9,10-dihydroxy-9,10-dihydrophenanthrene (phenanthrene trans-9,10-dihydrodiol). A trace of 9-phenanthrol was also detected. Metabolites isolated by thin-layer and high performance liquid chromatography were identified by comparing chromatographic, mass spectral, and nuclear magnetic resonance properties with those of authentic compounds. Experiments using [9-14C]phenanthrene showed that the trans-9,10-dihydrodiol had 62.8% of the radioactivity found in the metabolites. Circular dichroism spectra of the phenanthrene trans-9,10-dihydrodiol indicated that the absolute configuration of the predominant enantiomer was (–)-9S,10S, the same as that of the principal enantiomer produced by mammalian enzymes. Incubation of S. flavovirens with phenanthrene is an atmosphere of 18O2, followed by gas chromatographic/mass spectral analysis of the metabolites, indicated that one atom from molecular oxygen was incorporated into each molecule of the phenanthrene trans-9,10-dihydrodiol. Cytochrome P-450 was detected in 105,000×g supernatants prepared from cell extracts of S. flavovirens. The results show that the oxidation of phenanthrene by S. flavovirens was both regio- and stereospecific.Abbreviations CD
circular dichroism
- DMF
N,N-dimethyl-formamide
- GC/MS
gas chromatography/mass spectrometry
- HPLC
high performance liquid chromatography
- NMR
nuclear magnetic resonance
- ODS
octadecylsilane
- PAH
polycyclic aromatic hydrocarbon
- TLC
thin-layer chromatography
- TMS
tetramethylsilane
- UV
ultraviolet 相似文献
19.
Robert H. White 《Chirality》1996,8(4):332-340
The configuration at the C-9 of methanopterin (MPT) has been determined by comparing the circular dichroism (CD) spectra of MPT and its hydrolytic fragment, 1-[4-[[1-(2-amino-7-methyl-4-hydroxy-6-pteridinyl)-ethyl]amino]phenyl]-1-deoxy-D -ribitol (HP-1), with the CD spectra of a series of model compounds of known stereochemistry. These compounds included (S)-6-[1-(4-carboxymethylanilino)ethyl]pterin, (S-6(1-hydroxyethyl)-7-methylpterin, (S-6-(1-hydroxyethyl)pterin, (R)-6-(1-phenoxyethyl)pterin, D (+)-neopterin, and L -biopterin. From this comparison it was concluded that MPT has the R configuration at C-9 and is thus configurationally related to D (+)-neopterin, which has the S configuration at C-1. From previous work establishing the relative stereochemistry at C-6, C-7, and C-9 of N5-N10-methenyl-5,6,7,8-tetrahydromethanopterin (N5-N10-methenyl-H4MPT) as R, S, and R, respectively, it is clear that the remaining asymmetric carbons at C-6 and C-7 of H4MPT have the S and S configuration, respectively. Comparison of these latter two positions to the equivalent carbons in 5,6,7,8-tetrahydrofolate (H4folate) show that the steps involved in the biological reduction of MPT to H4MPT occur with the same stereochemical outcome as those involved in the biological reduction of folate to H4folate. © 1996 Wiley-Liss, Inc. 相似文献
20.
Summary
S-[2-Carboxy-1-(1H-imidazol-4-yl)ethyl]-3-mercaptopyruvic acid (I) was chemically synthesized in 15% yield by incubating a reaction mixture oftrans-urocanic acid and 3-fold excess of 3-mercaptopyruvic acid at 45°C for 6 days. The synthesized compound was characterized by fast-atom-bombardment mass spectrometry and high-voltage paper electrophoresis. CompoundI was identified with a product of an enzymatic reaction ofS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl]-l-cysteine (II) with rat liver homogenate in a phosphate buffer, pH 7.4. CompoundI was degraded toS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl]-3-mercaptolactic acid (III), a compound previously found in human urine [Kinuta et al. (1994) Biochem J 297: 475–478], by incubation with rat liver homogenate. From these results, we suggest that compoundI is a metabolic intermediate for the formation of compoundIII from compoundII. The present pathway follows a formation of compoundII fromS-[2-carboxy-1-(1H-imidazol-4-yl)ethyl] gluthathione [Kinuta et al. (1993) Biochim Biophys Acta 1157: 192–198], a proposed metabolite ofl-histidine. 相似文献