共查询到20条相似文献,搜索用时 31 毫秒
1.
Sodeoka M Sampe R Kojima S Baba Y Morisaki N Hashimoto Y 《Chemical & pharmaceutical bulletin》2001,49(2):206-212
RK-682 was reported to be a potent protein tyrosine phosphatase inhibitor. We found that (R)-3-hexadecanoyl-5-hydroxymethyltetronic acid (1) was easily converted to its calcium salt during column chromatography on Silica gel 60, and this calcium salt was identical to RK-682 originally isolated from a natural source. Here we report details of the asymmetric synthesis of (R)-1 and its conversion to the calcium salt. Fast atom bombardment mass spectrometric (FAB-MS) analysis of the free and calcium salt forms of RK-682 is also reported. 相似文献
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Morisaki N Kobayashi H Nagasawa K Baba Y Sodeoka M Hashimoto Y 《Chemical & pharmaceutical bulletin》2003,51(11):1341-1344
The FAB mass spectrum of the Ca(2+) salt of RK-682 (1, MW 368), a potent protein tyrosine phosphatase inhibitor, shows a complex pattern due to Ca(2+) adduct ions with multimers of 1 and their decomposition ions. Addition of LiCl greatly simplified the FAB mass spectrum, providing a prominent Li(+) adduct ion of 1 at m/z 381 [M+2Li-H](+). The addition of LiCl also greatly simplified the FAB mass spectrum of calcium pantothenate. This approach may be generally useful for molecular weight determination of multivalent metal salts of organic compounds, or organic compounds that can form Li salts, by FAB mass spectrometry. 相似文献
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The enzyme inhibitor RK-682 (5R)-(+)-1 was prepared in solution and on a solid support from (2R)-glycerates in five steps and ca. 40% overall yield. Key steps were a ring-closing tandem addition-Wittig alkenation reaction of the respective protected or immobilized glycerates with the ylide Ph(3)PCCO and the 3-acylation of the tetronic acids thus obtained with palmitic acid. A similar route extended by a mesylation-elimination sequence led to antibiotic agglomerins A-C 2 featuring 3-acyl-5-methylidenetetronic acid structures. 相似文献
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《Chemistry & biology》1997,4(4):279-286
Background: Since the molecular target of the immunosuppressive reagents FK506 and cyclosporin A was revealed to be protein phosphatase PP2B (calcineurin), many researchers have been screening the protein phosphatase inhibitors from microbial metabolites to develop new immunosuppressive reagents. We isolated stevastelin B, which is composed of valine, threonine, serine and 3,5-dihydroxy-2,4-dimethyl stearic acid, and stevastelin A, which is a sulphonylated derivative of stevastelin B. To understand the action mechanism of stevastelins A and B, we synthesized a series of stevastelin derivatives and investigated their structure-activity relationships.Results: A series of stevastelin derivatives have been systematically synthesized. Stevastelin B inhibited gene expression that is dependent on interleukin-2 (IL-2) or IL-6 promoters in situ, but it had no inhibitory activity against any protein phosphatases in vitro. In contrast, stevastelin A, which is a sulphonylated derivative of stevastelin B, inhibited the phosphatase activity of a dual-specificity phosphatase, VH1-related human protein (VHR), in vitro, but it had no inhibitory activity against gene expression or cell-cycle progression in situ.Conclusions: Stevastelin B is a novel immunosuppressant. It inhibited IL-2 or IL-6 dependent gene expression but did not inhibit the phosphatase activity of calcineurin. The structure-activity relationships show that the acidic functional group on the threonine residue and the stearic acid moiety in the stevastelin molecule are important for inhibitory effects on the dephosphorylation activity of VHR in vitro. Stevastelin B might be sulphonylated or phosphorylated after incorporation into the target cell, and then it interacts with protein tyrosine phosphatases and regulates cell-cycle progression. 相似文献
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Painelli A Terenziani F Angiolini L Benelli T Giorgini L 《Chemistry (Weinheim an der Bergstrasse, Germany)》2005,11(20):6053-6063
To investigate interchromophore interactions in azobenzene polymers, we have undertaken a thorough spectroscopic analysis of the azodye [(S)-3-pivaloyloxy-1-(4'-nitro-4-azobenzene)pyrrolidine] by modeling the repeating unit of poly[(S)-3-methacryloyloxy-1-(4'-nitro-4-azobenzene)pyrrolidine) and its dimeric derivative whose synthesis is presented here. The analysis of the electronic and Raman spectra of the azodye in several solvents is based on a previously proposed model for polar chromophores in solution. Electronic and CD spectra of the dimeric unit are collected and analyzed within the framework of a new model. On the basis of the information collected from the spectroscopic analysis of the solvated dye, this model accounts for interchromophore interactions in the dimer. The large CD signal measured for the dimer (amounting to about a third of the signal measured for the polymer) suggests the presence of important chiral interactions in the dimeric unit, and is modeled in terms of a right-handed relative orientation of the two chromophores. 相似文献
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Inhibition of 304 stainless steel corrosion in acidic chloride pickling (1.0 M HCl) solutions by newly synthesized oxazocine derivative 4 as a corrosion inhibitor have been studied using weight loss, potentiodynamic polarization, and atomic absorption spectroscopy investigations. Potentiodynamic polarization curves show that the inhibitor behaves as a mixed-type. The adsorption of the inhibitor on the metal surface in the acid solution was found to obey Langmuir’s adsorption isotherm. The inhibition mechanism of the investigated inhibitor was discussed in terms of its adsorption on the metal surface. The relationship between the molecular structure and the inhibition efficiency was elucidated by quantum chemical calculations. 相似文献
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Pterocaryquinone,a novel 1,4-naphthoquinone derivative,was isolated from Pterocarya tonkinesis and itsstructure was elucidated by spectroscopic methods.Pterocaryquinone is a new dimeric 1,4-naphthoquinone deriva-tive having a pentacyclic skeleton with two five-membered carbon rings,which provided a novel structural skeletonfor 1,4-naphthoquinone derivatives and showed apoptosis-inducing activity toward mouse cancer tsFT210 cells. 相似文献
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Lead tetraacetate oxidation of a Corynanthe-type indole alkaloid, mitragynine, produced mainly 7-acetoxyindolenine derivative (2) together with a dimeric compound (4) as a minor product. The novel structure having a bridge between the C-11' and C-7 positions in the respective indolenine parts and its formation mechanism were studied. 相似文献
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Dr. Hiroshi Hinou Risho Miyoshi Yasuaki Takasu Hirokazu Kai Dr. Masaki Kurogochi Dr. Shingo Arioka Dr. Xiao‐Dong Gao Dr. Nobuaki Miura Dr. Naoki Fujitani Dr. Shinya Omoto Dr. Tomokazu Yoshinaga Dr. Tamio Fujiwara Dr. Takeshi Noshi Dr. Hiroko Togame Prof. Hiroshi Takemoto Prof. Shin‐Ichiro Nishimura 《化学:亚洲杂志》2011,6(4):1048-1056
A potent inhibitor for Vibrio cholerae neuraminidase (VCNA) was developed by using a novel two‐step strategy, a target amino acid validation using mechanism‐based labeling information, and a potent inhibitor search using a focused library. The labeling information suggested the hidden dynamics of a loop structure of VCNA, which can be a potential target of the novel inhibitor. A focused library composed of 187 compounds was prepared from a 9‐azide derivative of 2,3‐dehydro‐N‐acetylneuraminic acid (DANA) to interrupt the function of the loop of the labeled residues. Inhibitor 3c showed potent inhibition properties and was the strongest inhibitor with FANA, a N‐trifluoroacetyl derivative of DANA. Validation studies of the inhibitor with a detergent and a Lineweaver–Burk plot suggested that the 9‐substitution group would interact hydrophobically with the target loop moiety, adding a noncompetitive inhibition property to the DANA skeleton. This information enabled us to design compound 4 having the combined structure of 3c and FANA. Compound 4 showed the most potent inhibition (Ki=73 nM , mixed inhibition) of VCNA with high selectivity among the tested viral, bacterial, and mammal neuraminidases. 相似文献
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We found that a fungus Neosartorya sp. produced an angiogenesis inhibitor, RK-805. By spectroscopic analyses and semi-synthetic methods from fumagillin, the structure of RK-805 was identified as 6-oxo-6-deoxyfumagillol, which has not been reported as a natural product. RK-805 preferentially inhibited the growth of human umbilical vein endothelial cells (HUVECs) rather than that of human normal fibroblast in cell proliferation assays and blocked endothelial cell migration induced by vascular endothelial growth factor (VEGF). Moreover, RK-805 selectively inhibited methionine aminopeptidase-2 (MetAP2), but not methionine aminopeptidase-1 (MetAP1). The docked structure of RK-805 complexed with human MetAP2 indicated that not only a covalent bond between a nucleophilic imidazole nitrogen atom of His231 and the carbon of the reactive spirocyclic epoxide of RK-805, but also a hydrogen bond between NH (Asn329) and the carbonyl group of RK-805 at C-6 promote close contact in the binding pocket of the enzyme. Taken together, these results suggest that structure activity relationships of RK-805 derivatives at both C-4 and C-6, in comparison with ovalicin and TNP-470, would be useful for development of new angiogenesis inhibitors. 相似文献
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Zhu W Fu A Hu J Wang T Luo Y Peng M Ma Y Wei Y Chen L 《Experimental & molecular medicine》2011,43(3):146-152
Our previous report has demonstrated that 5-formylhonokiol (FH), a derivative of honokiol (HK), exerts more potent anti-proliferative activities than honokiol in several tumor cell lines. In present study, we first explored the antiangiogenic activities of 5-formylhonokiol on proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs) for the first time in vitro. Then we investigated the in vivo antiangiogenic effect of 5-formylhonokiol on zebrafish angiogenesis model. In order to clarify the underlying molecular mechanism of 5-formylhonokiol, we investigated the signaling pathway involved in controlling the angiogenesis process by western blotting assay. Wound-healing results showed that 5-formylhonokiol significantly and dose-dependently inhibited migration of cultured human umbilical vein enthothelial cells. The invasiveness of HUVEC cells was also effectively suppressed at a low concentration of 5-formylhonokiol in the transwell assay. Further F-actin imaging revealed that inhibitory effect of 5-formylhonokiol on invasion may partly contribute to the disruption of assembling stress fiber. Tube formation assay, which is associated with endothelial cells migration, further confirmed the anti-angiogenesis effect of 5-formylhonokiol. In in vivo zebrafish angiogenesis model, we found that 5-formylhonokiol dose-dependently inhibited angiogenesis. Furthermore, western blotting showed that 5-formylhonokiol significantly down-regulated extracellular signal-regulated kinase (ERK) expression and inhibited the phosphorylation of ERK but not affecting the total protein kinase B (Akt) expression and related phosphorylation, suggesting that 5-formylhonokiol might exert anti-angiogenesis capacity via down-regulation of the ERK signal pathway. Taken together, these data suggested that 5-formylhonokiol might be a viable drug candidate in antiangiogenesis and anticancer therapies. 相似文献
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L-乳酸脱氢酶抑制剂抑制成因的探讨 总被引:1,自引:0,他引:1
应用HF/3 21G研究了抑制剂H2N-CO-COO-对L 乳酸脱氢酶的抑制成因.结果表明,酶被抑制的主要原因有:(1)抑制剂与底物的稳定构象态在结构上极为相似,导致酶不能有效识别底物;(2)模型抑制剂各原子所带净电荷的优势使抑制剂更易与酶活性中心结合;(3)抑制剂通过对酶的诱导契合作用使酶活性中心的空间被缩小;(4)对活性中心有关结构的分析表明,底物的甲基分子片以及酶的氨基酸残基Gln 102,对催化反应能否顺利进行,影响极大. 相似文献
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Binding of a dimeric derivative of vancomycin to L-Lys-D-Ala-D-lactate in solution and at a surface.
BACKGROUND: The emergence of bacteria that are resistant to vancomycin (V), a glycopeptide antibiotic, results from the replacement of the carboxy-terminal D-Ala-D-Ala of bacterial cell wall precursors by D-Ala-D-lactate. Recently, it has been demonstrated that covalent dimeric variants of V are active against vancomycin-resistant enterococci (VRE). To study the contribution of divalency to the activities of these variants, we modeled the interactions of V and a dimeric V with L-Lys-D-Ala-D-lactate, an analog of the cell-wall precursors of the vancomycin-resistant bacteria. RESULTS: A dimeric derivative of V (V-Rd-V) was found to be much more effective than V in inhibiting the growth of VRE. The interactions of V and V-Rd-V with a monomeric lactate ligand - diacetyl-L-Lys-D-Ala-D-lactate (Ac2KDADLac) - and a dimeric derivative of L-Lys-D-Ala-D-lactate (Lac-R'd-Lac) in solution have been examined using isothermal titration calorimetry and UV spectroscopy titrations; the results reveal that V-Rd-V binds Lac-R'd-Lac approximately 40 times more tightly than V binds Ac2KDADLac. Binding of V and of V-Rd-V to Nalpha-Ac-L-Lys-D-Ala-D-lactate presented on the surface of mixed self-assembled monolayers (SAMs) of alkanethiolates on gold indicates that the apparent off-rate for dissociation of V-Rd-V from the surface is much slower than that of V from the same surface. CONCLUSIONS: The results are compatible with the hypothesis that divalency is responsible for tight binding, which correlates with small values of minimum inhibitory concentrations of V and V-Rd-V. 相似文献
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Umeda Y Furihata K Sakuda S Nagasawa H Ishigami K Watanabe H Izumikawa M Takagi M Doi T Nakao Y Shin-ya K 《Organic letters》2007,9(21):4239-4242
In the course of our screening program for regulators of a molecular chaperone GRP78 expression, we isolated a novel inhibitor of GRP78 expression, designated as prunustatin A, from Streptomyces violaceoniger 4521-SVS3. The planar structure of prunustatin A was determined to be an oxidized type of the neoantimycin family. Its absolute stereochemistry was established to be 2R, 4S, 6S, 7R, 9S, and 29S by analyzing chemically degraded components obtained from the derivative of prunustatin A. 相似文献
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Dušan Sokolović Veroljub Stanković Dragan Toskić Ljubiša Lilić Goran Ranković Jasmina Ranković Gorana Nedin-Ranković Aleksandar M. Veselinović 《Structural chemistry》2016,27(5):1511-1519
The Monte Carlo method was used for QSAR modeling of dimeric pyridinium compounds as acetylcholine esterase inhibitors. QSAR model was developed for a series of 39 dimeric pyridinium compounds. QSAR models were calculated with the representation of the molecular structure by the simplified molecular-input line-entry system. One split into the training and test set have been examined. The statistical quality of the developed model is very good. The calculated model for dimeric pyridinium derivatives had following statistical parameters: r 2 = 0.9477 for the training set and r 2 = 0.9332 the test set. Structural indicators considered as molecular fragments responsible for the increase and decrease in the inhibition activity have been defined. The computer-aided design of new dimeric pyridinium compounds potential acetylcholine esterase inhibitors with the application of defined structural alerts has been presented. 相似文献
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Hirotsugu Kobayashi Koji Nagai Nobuhiro Fusetani Shigeki Matsunaga 《Tetrahedron letters》2007,48(12):2127-2129
A new dimeric oroidin derivative, carteramine A (1), was isolated as a neutrophil chemotaxis inhibitor from the marine sponge Stylissa carteri. The structure of 1 was elucidated by the analysis of spectral data. 相似文献